Fixed potential leak in MessagePackParser.
Fixed warnings for potential leak in GeneralPurposeParser.

Stupid analysis tool expects certain names for methods that return newly alloc'ed objects. We can choose between "alloc*", "new*", "copy*". Using "alloc" or "new" causes new warnings about semantics, so we end up with "copyUnpackedObject". Stupid.
Updated to latest version of msgpack-c.

Commit 9f33266f235d1b253b66e61103852a2a5d30152d from https://github.com/msgpack/msgpack-c (0.5.8 snapshot).
Updated podpec for release 1.2.5.