The Makefile used to suppress output (by using @), so this target made sense at
the time.

But the Makefile should be simple and make debugging with less abstractions or
fancy printing.  The Makefile was made verbose and doesn't hide the build
output, so remove this target.

Prompted by a question on the mailing list about the options target.

Don't be fancy and just show the actual output so debugging is simpler.

... also some style improvements.

- libdraw, util: add drw.{c,h}, util.{c,h} and update code.
- libdraw: fix drw_rect(): use w and h parameter.
- libdraw: print errstr if last character in string was ":" (sbase).
- libdraw: drw_clr_free() allow valid free(NULL).
- config.def.h: set default font to monospace.
- cleanup() on exit.
- LICENSE: update license string for dmenu -v to 2015.
- LICENSE: add myself to LICENSE

This allows to run dmenu_path to update the cache using
a packager manager hook system