Revert "Revert "Normalize potmeter widget values to [0.0, 1.0] instead of [0.0, 127.0].""

This reverts commit 6fcd283cd80a34747320340ecc9a17b9b4b9606a.
Minor refactoring in Midi to Control path
Merge pull request #2 from daschuer/potmeter_fix

Minor refactoring in Midi to Control path
Fix WKnob / WDisplay active pixmap calculation to bias towards the lower of the two middle pixmaps when there are an even number.
Rename widget parameter to parameter.
Merge pull request #143 from rryan/potmeter_fix

Normalize potmeter widget values to [0.0, 1.0] instead of [0.0, 127.0].