The pep states load_module must return whatever exists on sys.modules
or the reload will not work. In practice that blocks the reload
from doing anything. Now ignoring sys.modules, because by the time
code is asking for load_modules, the system has already done its
exhaustive searching.

Remember there are suffixes for importing that are not file extensions.
On Linux there is "module.so", which needs better handlig than
os.path.splitext.

There were some confusing misuses of different names inside different
blocks. Also crush out remaining mixedCase names.