Bugfix/latch velocity modwheel

[m-m-adams]

Fix a bug where releasing a pad recalculated the display value, leading to changes when the display value was different between calculations. Now releasing always latches the value set during the press.

Fix a bug where releasing the top pad after changing columns caused the new column to treat that as a release. Fixed by setting that pad as "dead" when it's used to change columns so no release is processed

Fix #2155

Fix velocity column initialization to make display match the held value

Fix #2156 (just the definitely buggy part)

[github-actions[bot]]

Test Results

46 tests  ±0   46 :white_check_mark: ±0   0s :stopwatch: ±0s  8 suites ±0    0 :zzz: ±0   8 files   ±0    0 :x: ±0 

Results for commit 456d7166. ± Comparison against base commit 50a0cbac.