v0.44

 - Update libgit2 to fa44a16 (GH#120)
 - Added Remote methods (GH#120):
    + default_branch
 - Stash -> save() now returns a true value if files were stashed, and undef
   if nothing was stashed (GH#121). (Potentially incompatible change if you
   relied on the function die'ing if there was nothing to be stashed)
 - Commit -> parents() and Tree -> entries() now return lists as per the
   documentation (GH#122)
 - Config -> foreach(), Stash -> foreach() and Tag -> foreach() now correctly
   aborts the iteration. Previously it would die if the user requested
   termination of the loop with a return value that is not GIT_USER. (GH#123)