relay U:free to Udef
set canUseUMap to false for FuncUMapDef
introduce UMapDef:activateUnit

this starts the UMap if it's parent unit is already playing
add ValueUMapDef

this def is the basis for midi and osc support, and can hold and manage
routines.
add midi_cc UMapDef
change category of sine UMapDef to '(depricated)'

so that it looks clearly different in UMapDefListView
reshuffle invert/curve args in various UMapDefs
add safety clipping to args of various Udefs

in case something goes odd with the mappers