Finishing the move of Extensions=>extensions.

Moving Extensions=>extensions the long way. OS X is case insensitive, so I can't do the move directly. This is an intermediate step.

Added compatibility layer for Shell/ipapi/iplib. These 3 top-level modules have been moved to core. But, to ease the transition to their new location, we have re-created these modules at the top-level. The new top-level modules print a warning statement and simple import the moved modules for now. In the long run, we can use these for further compatibility related things.

Fixing a few bugs to get the win32 installer working again.

Adding missing __init__.py.

Fixing installation related issues.

Removing old testing/tutils.py file that is no longer used.

Moving things from tools to new utils directory.

UserConfig => config/userconfig and imports updated.

Removing empty and unused top-level tests directory.