Added runtime reconfigurability to the WH base

RM6914

Fixed flake8 errors.

Added notes about calling super's __call__
Merge pull request #50 from roaet/runtime_reconfigure

Added runtime reconfigurability to the WH base.
Support for disabling waffles runtime

All waffles will now support being en/disabled during runtime through a header
X_WAFFLEHAUS_*classname_uppercase*_ENABLED.

Similarly they support having themselves toggled between testing/not testing
with X_WAFFLEHAUS_*classname_uppercase*_TESTING.
Merge pull request #51 from roaet/runtime_reconfigure

Support for disabling waffles runtime