100% velocity should be 100%

Turns out many midi based instruments (soundfonts, zyn presets, etc) use the velocity data for more than just volume. A recent change (0ca3901ab86006d775125f6a5caf70d873bf008b) changed the scale so that what is 100% for lmms is only 50% (63) for midi based instruments. As a result the instruments may sound noticeably duller.

This change reverts 0ca3901ab86006d775125f6a5caf70d873bf008b and ba324f4aa86ef6362b0338b35dedc50ef2e5e42a so that midi velocity is now capped to 127.