Cleanup filetype_make_title() a bit and use it more
* Adds TITLE_NONE, TITLE_SCRIPT and TITLE_DOCUMENT.
* Only a few filetype titles were tweaked but we should review the
rest as we could use TITLE_SCRIPT and TITLE_DOCUMENT a lot more
* Make filetype_make_title() not care about GeanyFiletype type and
return result instead of internally setting ft state.