eina_str speedups.

eina_str speedups.

 * eina_str_split() now does the minimum number of passes and
   allocations. The first pass figures out the string size (strlen())
   and number of delimiters, so we can allocate the exact number of
   elements in array. The second repeats the loop copying elements to
   string and also setting them to the result array.

 * eina_str_split_full() is a variation of eina_str_split() that
   returns also the number of elements in array, in the case you need
   to pre-allocate another array to copy.

 * eina_strlen_bounded() is introduced to limit strlen() results, this
   is used in has_prefix and has_suffix, but possibly other use cases
   where string must be of a maximum size as we don't do useless
   iterations;

git-svn-id: svn+ssh://svn.enlightenment.org/var/svn/e/trunk/eina@46547 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33