Merge pull request #76 from krnekhelesh/master

Added debian packaging documentation and PPA installation notes
Various improvements
Added an about page
Version 0.2.1
Fixed #77 and #78
Updated icons and worked on deb packaging
Released v0.2.2
Added Events plugin
Fixed bug for comment and close/reopen action
Improvements to the Events, Timer, and Travis CI plugins
Hid progress label used for debugging
Finished redoing the Notes plugin
Added overview value for plugins
Added unit tests for adding/removing plugins
Small refinements to various plugins
New sync framework and UI
Small tweaks
Display plugin icons in the configuration page
Close the sync popover when the sync is finished
Affected bugs in the README