Made the distutils extension 2.3 compatible
Renamed the --debug flag to --gdb and --pyrex-debug to --pyrex-gdb

--HG--
extra : rebase_source : 7fea7f050894df69b66a2bdb843ce1885ef7ef7a

fix ticket #578 by working around CPython bug 9834: crash in Py3.[0-1.2] when slicing non-sliceable objects

C function with context support
Preliminary stepping support
Source code listing
more stuff I forgot about

This is cleaner and has consistancy with how we handle removed PyInt* stuff.

Fix #566, where __getslice__ generates code that gives a confusing compiler error under Python 3.  (Now you get a Cython compiler warning and a direct error message.)  A modification of the patch for #215.

- Silent compiler warnings about unused function/parametes
- Defined to __attribute__((__unused__)) for GCC(>3.4) and ICC
- Applied to a __{get|release}buffer__ special methods
- Applied to a couple of (self,unused) parameter pairs