SDK: Moved all codelite internal events to a new file "codelite_events.h"
SDK: changed wxEVT_FILE_SAVED and other file management events to use clCommandEvent (was: wxCommandEvent)
Diff Viewer: fire a "wxEVT_FILE_SAVED" when a modified file is saved
Diff Viewer: afer save is done, post a ReloadExternallyModifiedEvent event