complete struct stat in POSIX API

generally postpone the cleanup for char* temps to improve safety and move the 'char* from temp' compile error to assignments to allow non-trivial char* expressions

--HG--
rename : tests/run/charptr_cfunc_args.pyx => tests/run/charptr_from_temp.pyx

keep Python string object references alive across temp cleanup until disposal (e.g. during function calls that take them as arguments)

cython-mode.el: add missing grouping to keyword regexps

* fix font-locking of keyword regexps (matcher was referring to group
  that ceased to exist after 0a7e8d60)

* fix adding customized font-lock-keywords

  Old code behaved bad because it changed an element of a list that was
  compiled into "python-mode" function definition.  This had an
  unfortunate side effect of propagating cython-specific keywords into
  vanilla python buffers.

* fontify new types in ctypedef statements

* add more keywords ("cppclass", "new", "del", etc.)

* add more builtin types ("Py_UNICODE", "ptrdiff_t", etc.)

* fix font-locking of "except?"

* fontify types with font-lock-type-face, not py-class-name-face

Conflicts:
	CHANGES.rst