Revert "pyximport: parse distutils config files (except local setup.cfg)"

This reverts commit 813ff05a80cef908704488e660fa07d49feb8a92.

This was an accidentally applied twice.
use all distutils config files

It is very astonishing to a user, that pyximport uses a different
set of config files from the underlying distutils.
Dissallow Python 2.4, 2.5, 3.0, and 3.1
Remove obsolete utility code.
More obsolete code removal.
Check for Python 2.6+
More cleanup.
Restore some over-eager 3.1 removals.
Remove another py_set utility code reference.
uncomment vector assign function template
cython-mode.el: don't highlight builtins when they're part of varname

To avoid mismatches keywords should be checked at symbol, not word
boundaries, otherwise they'll ignore underscores (is_*float*).
remove unreachable code
use context manager to close file, and more explicit variable name
move first part of the logic into a wrapping function

this should help to decouple from the filesystem and heuristic in
filenames
add a directive to disable SwitchTransform

SwitchTransform is unable to detect all cases of duplicate values, which
result in errors at compile time in the generated code.
make _save annotation a io-less method
fix accidental removal of a line
clearup unused arguments and close P tags
split _save_annotation on multiple function

will allow refactor of the cython magic not to parse temporary files
and not to leak css into IPython notebooks
add unique class name to avoid conflic

in particular tings like 'code' are conflicting when embeding the page