Remove Awkward Stretching of Config Widgets

When the config tool's window size is stretched, the components stretch
awakardly (ex. 4 lines will be evenly distributed over the entire
height of the window). This commit fixes this by adding a stretch
factor of 0 to the main layout.

Close #518
Related to #411
Signed-off-by: Thanh Ha <thanh.ha@alumni.carleton.ca>
Added about tab, contains same things as general tab
added some content to about tab, set stretch to 0, preventing the tab from stretching awkwardly when the screen is resized.
Added to the about tab, including buttons. BUTTONS DO NOT HAVE ANY ACTION
about tab being implimented using the aboutDialog
moved AboutWidget.py to qtCommon folder
changed config tool test to assert that active widget on opening is AboutWidget, not General. All other changes are for style
updated unit test for config tool
fixed up according to @zero57's comments on github
Fixed according to @zero57's comments on github
modified for style
style fixes for travis
dialog window title
fixed typo on help button
added translations for button text