* luacheck: enable cache
* Cleanup .gitignore: remove .build* and awesome
We only use the "build" dir by now, where also the "awesome" binary gets
created.
This commit adds a new "luacheck" target to the Makefiles. This target is
automatically included in "make check" when luacheck is found in $PATH.
Additionally, this includes luacheck in Travis so that the build fails when
luacheck complains about something.
Signed-off-by: Uli Schlachter <psychon@znc.in>
