Improve error messages on circle CR and 2PR draw actions. ref issue #…

…1514

Added error messages on tangential 2 circles + radius draw action.

Fix error handling on circle CR and 2PR draw actions. ref issue #1514

Merge branch 'master' of git@github.com:pollywinters/LibreCAD.git int…

…o local

release candidate 3 for 2.2.0

changed Help->Online->Commands link, fixes #1215

refactoring of RS_DimAngular, fix #911 and #824/#896

returning to LC via Command+Tab won't always activate a subwindow #821 …

…#814

eliminated build error for gcc 5.4

8bedeb5751ac0b3490b9d5395741
687fc774eae9

ensured that draft mode is set for new drawings; #749

set LC_VERSION="2.2.0-alpha"