minor code simplification in utility functions by using macro for Py2/3 dependent PyString/PyUnicode_FromString() calls

avoid keeping a module reference in the CyFunction struct as long as we don't really need it (func_globals isn't really an every days API)

Fix a couple of typos in distutils docstrings

Signed-off-by: Yury V. Zaytsev <yury@shurup.com>

Fixing bug which would reference an unbound local variable

Fixing bug which would reference an unbound local variable. Should reference "self.visibility" instead of visibility.

Final and inline method support

Wrong Example in "Sharing Declarations Between Cython Modules"

report filenames relative to the current directory or as absolute paths i

we use relative filenames for files in the directory itself or
subdirectories, absolute paths otherwise.

this makes cython compatible with emacs compilation mode.

fix PEP-393 error case in __Pyx_UnicodeContainsUCS4() by handling all possible cases separately; clean up redundant code