LT-15137: FB Crash when Proj Dirs Mismatch

When a user ran FlexBridge from a project not in the FLEx
default projects directory, FB complained and quit. Fixed:
Don't check whether Proj is in Default Projects Directory.
Don't run unnecessary checks when checking for FB updates.
Update unit tests.
Update release notes
Fix path for L10NSharp to its new location
Build Script Updates
Merge branch 'Beta' of git://github.com/sillsdev/flexbridge into Beta
Update Linux packaging for new beta release

Also fix a build problem with L10NSharp location.
Merge: Beta->master