Fix "Assignment to constant variable." error

Fix C source code files' type

The correct file type string is `sourcecode.c.c` and not `sourcecode.c`

Merge pull request NativeScript#7 from NativeScript/tdermendzhiev/fix…

…-root-group-duplication

bugfix: Remove group reference from root group after group removal

Merge pull request NativeScript#5 from e2l3n/tpopov/rebase-onto-origin

Rebase origin onto master

Merge pull request NativeScript#4 from NativeScript/fatme/fix-remove-…

…framework

Fix framework remove function

Merge pull request NativeScript#1 from NativeScript/fatme/improvements

Fix quotes and lastKnownFileType

Fix setting build configuration properties

Bump version to 0.6.2.