Added Discord link

I also fixed a few grammatical errors

README.md

@@ -3,12 +3,13 @@ OpenSensorHub
 
 [![Build Status](https://travis-ci.org/opensensorhub/osh-core.svg?branch=master)](https://travis-ci.org/opensensorhub/osh-core)
 [![GitHub Release](https://img.shields.io/github/release/opensensorhub/osh-core.svg)](https://github.com/opensensorhub/osh-core/releases/latest)
+[![OpenSensorHub Discord](https://user-images.githubusercontent.com/7288322/34429117-c74dbd12-ecb8-11e7-896d-46369cd0de5b.png)](https://discord.gg/6k3QYRSh9F)
 
-OpenSensorHub (OSH) software allows one to easily build interoperable and evolutive sensor networks with advanced processing capabilities and based on open-standards for all data exchanges. These open-standards are mostly [OGC](http://www.opengeospatial.org) standards from the [Sensor Web Enablement](http://www.opengeospatial.org/projects/groups/sensorwebdwg) (SWE) initiative and are key to design sensor networks that can largely evolve with time (addition of new types of sensors, reconfigurations, etc.).
+OpenSensorHub (OSH) software allows one to easily build interoperable and evolutive sensor networks with advanced processing capabilities and based on open standards for all data exchanges. These open-standards are mostly [OGC](http://www.opengeospatial.org) standards from the [Sensor Web Enablement](http://www.opengeospatial.org/projects/groups/sensorwebdwg) (SWE) initiative and are key to design sensor networks that can largely evolve with time (addition of new types of sensors, reconfigurations, etc.).
 
-The framework allows one to connect any kind of sensors and actuators to a common bus via a simple yet generic driver API. Sensors can be connected through any available hardware interface such as [RS232/422](http://en.wikipedia.org/wiki/RS-232), [SPI](http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus), [I2C](http://en.wikipedia.org/wiki/I%C2%B2C), [USB](http://en.wikipedia.org/wiki/USB), [Ethernet](http://en.wikipedia.org/wiki/Ethernet), [Wifi](http://en.wikipedia.org/wiki/Wi-Fi), [Bluetooth](http://en.wikipedia.org/wiki/Bluetooth), [ZigBee](http://en.wikipedia.org/wiki/ZigBee), [HTTP](http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol), etc... Once drivers are available for a specific sensor, it is automatically connected to the bus and it is then trivial to send commands and read data from it. An intuitive user interface allows the user to configure the network to suit its needs and more advanced processing capabilities are available via a plugin system.
+The framework allows one to connect any kind of sensor and actuator to a common bus via a simple yet generic driver API. Sensors can be connected through any available hardware interface such as [RS232/422](http://en.wikipedia.org/wiki/RS-232), [SPI](http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus), [I2C](http://en.wikipedia.org/wiki/I%C2%B2C), [USB](http://en.wikipedia.org/wiki/USB), [Ethernet](http://en.wikipedia.org/wiki/Ethernet), [Wifi](http://en.wikipedia.org/wiki/Wi-Fi), [Bluetooth](http://en.wikipedia.org/wiki/Bluetooth), [ZigBee](http://en.wikipedia.org/wiki/ZigBee), [HTTP](http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol), etc... Once drivers are available for a specific sensor, it is automatically connected to the bus, and it is then trivial to send commands and read data from it. An intuitive user interface allows the user to configure the network to suit its needs, and more advanced processing capabilities are available via a plugin system.
 
-OSH embeds the full power of OGC web services ([Sensor Observation Service](http://www.opengeospatial.org/standards/sos) or SOS, [Sensor Planning Service](http://www.opengeospatial.org/standards/sps) or SPS) to communicate with all connected sensors in the network as well as to provide robust metadata (owner, location and orientation, calibration, etc.) about them. Through these standard, several SensorHub instances can also communicate with each other to form larger networks.
+OSH embeds the full power of OGC web services ([Sensor Observation Service](http://www.opengeospatial.org/standards/sos) or SOS, [Sensor Planning Service](http://www.opengeospatial.org/standards/sps) or SPS) to communicate with all connected sensors in the network as well as to provide robust metadata (owner, location and orientation, calibration, etc.) about them. Through these standards, several SensorHub instances can also communicate with each other to form larger networks.
 
 Low level functions of SensorHub (send commands and read data from sensor) are coded efficiently and can be used on embedded hardware running [Java SE®](http://www.oracle.com/technetwork/java/javase), [Java ME®](http://www.oracle.com/technetwork/java/embedded/javame) or [Android®](http://www.android.com) while more advanced data processing capabilities are fully multi-threaded and can thus benefit from a more powerful hardware platform (e.g. multi-processor servers or even clusters).
 
@@ -29,7 +30,7 @@ This other [Technical Page](http://sensiasoft.net:8181/demo.html) contains examp
 
 ## Building
 
-OpenSensorHub can be built using Gradle either from the command line or within Eclipse. Please see the [Developer's Guide](http://docs.opensensorhub.org/dev/dev-setup) for detailed instructions.
+OpenSensorHub can be built using Gradle, either from the command line or within Eclipse. Please see the [Developer's Guide](http://docs.opensensorhub.org/dev/dev-setup) for detailed instructions.
 
 
 ## Contributing
@@ -39,3 +40,5 @@ Refer to the [Developer's Guide](http://docs.opensensorhub.org/dev/dev-guide/#bu
 You can also find useful information in the [Javadocs](http://docs.opensensorhub.org/dev/javadoc/) and Design Documentation on the [Wiki](../../wiki/Home). 
 
 Several sensor driver examples are also available in the source code to help you get started.
+
+Join our Discord to offer feedback!