add IPython notebook screenshot to the docs

avoid LLVM warning: skip ternary operator when value is unsigned

Change how posix/time.pxd is split up

Of course it's "cdef char *foo()" not "cdef char* foo()"

Also fix a potential bug with self.to_py_function beign assigned to soon.

--HG--
extra : transplant_source : %279%83%AB%FF%04%F0%F6%12%BB%D1P%19%A9%B9%F2%C6%C23%B6

--HG--
extra : transplant_source : %DA%97_%C9%8A%9E%ED%3F7%FC4m%1E%E6%0E%D3%89l%DF%D4

seems that allowing C functions without argument names to coerce to Python functions goes wrong (note: Python coercion is attempted more often than needed!)

reuse existing types/names in module for cfunc wrapping instead of redeclaring them in the utility code