* Make CI happy with code style on master
* guiFileSelectMenu: remove useless includes
* some performance fixes pointed by cppcheck
* remove some useless casts
* TextDest: remove unused setFormSpec function
Use wide_to_utf8 and utf8_to_wide instead of wide_to_narrow and narrow_to_wide at almost all places.
Only exceptions: test functions for narrow conversion, and chat, which is done in a separate commit.