This commit seems to break the py3k build.

This reverts commit b50c6792.

optimise dict.setdefault() - would be better in Builtin.py, but class scopes don't seem to support signature overloading yet

--HG--
extra : rebase_source : d0f2bd97e0cec8919ac00e9a0ec8b714e338a9cb

Support for typed memoryviews, memoryview objects & cython.array

initializedcheck directive + uninitialized memslice checking + memoryview indexing object<->dtype conversion