in pure mode: rename 'with nogil' to 'with cython.nogil', test 'real' pure mode by compiling .py file instead of .pyx file

--HG--
rename : tests/run/pure.pyx => tests/run/pure_py.py

move 'official' version number to Cython/__init__.py to avoid importing the complete compiler package for a version check

new autotestdict.{cdef,all} directives that put cdef and non-doctest docstrings into __test__, skip non-doctest docstrings by default

--HG--
rename : tests/run/autotestdict.pyx => tests/run/autotestdict_all.pyx
rename : tests/run/autotestdict.pyx => tests/run/autotestdict_cdef.pyx

fix octal literals as Python constants, convert octal/binary/hex integer literals to plain decimal integers when using them as Python integers

reverted support for cdef functions in __test__ dict: increases module size and init code but rarely helps

enable doctests in cdef functions/methods, do not rewrap docstrings in __test__ dict as EncodedString() but keep them as they are

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

store docstrings directly in the dict instead of looking them up at module init time
=> much faster, a lot less code, fewer redundant string constants (duplicate strings are unified anyway), and just as good, as docstrings of Cython functions/methods can't currently be changed anyway