attempt to fix image preload thread bugs 1: module refcount.

attempt to fix image preload thread bugs 1: module refcount.

image preload will use modules from threads, there is a possibility to
crash due wrong reference counting.

actually much more can fail, we need to check modules don't keep that
needs exclusive access in globals or per-Evas_Module, but that's
another issue.

TODO: replace spinlocks with atomic operations.

git-svn-id: svn+ssh://svn.enlightenment.org/var/svn/e/trunk/evas@38309 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33