API BREAK: eina_magic_string_set() does not change existing strings anymore.

API BREAK: eina_magic_string_set() does not change existing strings anymore.

It's pointless to be able to change magic number string after it's
created, so let's avoid walking the existing list and just remove
places where strings were being duplicated (list/array both inited
magic strings for accessor/iterators).

Also an optimization, register using an array and sort it before
searching. Sort will just happen when array was changed, and this is
just done when eina_magic_string_get() is called.

git-svn-id: http://svn.enlightenment.org/svn/e/trunk/eina@42310 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33