Don't use ctags types inside Geany

Don't use ctags types inside Geany

We should isolate ctags from Geany completely and use separate types. At
the moment langType is shared by both Geany and ctags. For Geany redefine
it as TMParserType (which was currently used as the name of the enum and
was unused) and use everywhere in Geany. At the same time convert some
ints to TMParserType where they denote the parser.

This is strictly speaking an API change but no plugin uses langType at the
moment so its renaming doesn't cause any problems.

The only remaining visible ctags type is tagEntryInfo - it is however
used only inside tagmanager (and can be later removed quite easily too
by slightly reorganizing TM source files).