Formerly bad code involving unassigned reference temporaries was generated.

Now that we split CInitCode and CppInitCode, we no longer generate
valid C code even if C++ features are not used.

Were these ever used, this would have been an error.

This not only fixes bugs like auto-conversion of std::map[enum, enum] but also
fixes a bug where the compiler-chosen type of int for the enum may not have been
long.

This is a bit of a hack, but as Cython doesn't yet understand
const overloads with different (usually const) return types,
it can't provide the right type of reference in this case.

Fixed some memory leaks in Utility/Embed.c

Fixed __Pyx_sst_abs with C++11

Found by clang's static analyzer.
None of those are significant, but we might as well fix them.

Some compilers appear to require you to explicitly `#include <cstdlib>` before
providing `std::abs`.

deep-copy finally clauses of try-finally statements earlier to properly support arbitrary statements in them (genexprs, lambdas, etc.)