(a) The code model manager figures out by itself which files were added
or removed from the project.
If this was done successfully, check also the timestamp of the
common files and reindex if necessary.
(b) A full reindexing is only triggered if the project configuration
changes (defines, includes, framework paths).
(c) If project files were removed, the garbage collector is called.
Reviewed-by: Fawzi Mohamed <firstname.lastname@example.org>