Use TMxpElement as a value class to avoid memory leaks.
Merge branch 'release_31' into development

Use TMxpElement as a value class to avoid memory leaks.
Move .clang-format to src directory.

Less unnecessary files in the top directory.
Merge pull request #116 from ahmedcharles/clang_format

Move .clang-format to src directory.
Refactor dlgProfilePreferences.h/cpp.

Now there is less code duplication. This also fixes a bug where the 'set
colors to default' button didn't work for the map panel.