Static analysis fix: Fixed leaking Objective-C object.

--HG--
extra : histedit_source : 0da11a53d41a0313aad9dc207f6b65ac5644128d
Static analysis fix: uninitialized variables.

This is actually a false-positive, in this case, since Clang doesn't know
 that SDL_SetError() only ever returns -1. Feature request to improve that,
 with explanation about these specific SDL patches, is here:

   http://llvm.org/bugs/show_bug.cgi?id=19208

--HG--
extra : amend_source : 7f0edf8fe0831e961cf800278174eebe915b3974
extra : histedit_source : 6c84fc38936198a2208e3e66b55130eb63262990
Static analysis fix: division by zero.

--HG--
extra : histedit_source : 6f8f18284e016f09e4950279524047f97da0294a
Static analysis fix: let clang know _this->displays isn't NULL.

--HG--
extra : histedit_source : 99316ad09963ca7e5928612b373cbb83dfda8530
Static analysis fix: dereference of a NULL pointer.