Added doxygen documentation file
 - Added doxygen configuration
 - Added custom doxygen theme
Added intial documentation for IConfig.
Merge branch 'feature/doxygen' into develop
Documented most of Base classes
Adds stubs of missed interface types.
Fixes crash in config value retrieving when user config doesn't exist.
Revert "Adds stubs of missed interface types."

This reverts commit 6b3d948f97eef8918f3fe29569609ffb77504b9f.
Fixes incorrect null checking of dynamic object in Config.
Merge branch 'develop' into feature/folder-panel