let FileType manage clighter
refactor: detach ClangService from clighter.vim
autostart Clighter only once time
fix passing wrong compile option bug
change default compile option to "-Iinclude -x c++"
remove unecessary autocmd
better handle for FileType event
update doc
Merge remote-tracking branch 'bbchung/master'

Conflicts:
	autoload/clighter.vim
	plugin/clighter.vim