Release v2.1.3 - minor changes

This is a patch release that fixes a bug introduced in former v2.1.1 and combines changes that were made in v2.1.1 and 2.1.2 (which have been removed):

Added plot scrolling using keyboard arrow keys
Added sorting to columns selection on filter screen
Code change for Log Stats to preserve previous drop-down selection when loading new log file
Updated Log View usage