edje: add edje_watch.

edje: add edje_watch.

edje_watch call edje_cc and monitor all the source file (edc, font
image, sound). If any of them change, it call edje_cc, update its
watching list and so on. edje_watch as the same command line as
edje_cc.
   Still a little bit rought, but it's the beginning of an interesting
experiment.

git-svn-id: svn+ssh://svn.enlightenment.org/var/svn/e/trunk/edje@70872 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33