Release v0.3.2

• improved logging output in command-line scripts (eg pww-classifier)
• added sub-command freeze to the pww-packages command-line tool to output the currently installed packages in pip-like format (unofficial packages get URL appended) either to stdout or to text file (eg requirements.txt)
• the sub-command install of the pww-packages command-line tool can process a requirements text file now as well
• added pww_version() function to weka.core.version to obtain the installed version of python-weka-wrapper3
• added with_graph_support() function to weka.core.version to see whether python-weka-wrapper3 has support for graphs using pygraphviz
• added with_plot_support() function to weka.core.version to see whether python-weka-wrapper3 has plotting support via matplotlib
• added sub-command bootstrap to the pww-packages command-line tool to output a Python script that can reinstall python-weka-wrapper3 and all the packages in another virtual environment or even another machine
• added is_official_package function to weka.core.packages module to check whether a package is an official one from the Weka package repository or not