Buttons can be turned on/off per view and setting.

Lizard needs to be easier to use so we can disable buttons now and
fixed some pep8,
added tests,
moved some tests to test_appview.py.
Fixed typo. Thanks to @reinout for spotting it.
Merge pull request #25 from lizardsystem/roland-friendly

Buttons can be turned on/off per view and setting.