Move md-cell display logic to css
remove useless comment
Fix bug in bounded int/float logic.
Added test
update to warnings
Update path.py

change str formatting to repr representation.
Use contentEditable to allow modification via the the slider readout
Add support to the float slider
Add keydown listener to commit changes on <enter>
Ignore the event object for handleTextChange
Add support for parsing pairs of numbers for range sliders
Change _parse_text_input to _parse_value and update float range regex
Fix infinite loop typo
Fix notify_trait getting called too early.
Handle 'deletable' cell metadata
Add tests for undeletable cells
Make cell be undeletable ONLY when metadata is explicitly false
Fix tests
Properly mock winreg functions for test

Fixes a lot of test failures on Python 3.4 on Windows, caused by
importlib trying to use our mocked out winreg functions when
reload(path) was called.
put back null gui hook for osx

`--gui osx` doesn't make sense on its own,
but it's called by `--matplotlib osx`,
which does.