UMapGUI first iteration

not perfect yet, but it works
UMap gui next iteration

drag and drop from from (new) UMapDefListView now works. UMaps can only
be dragged to args with ControlSpec or FreqSpec for now.
correct UMap dragging for Qt

still crashes in 3.5, but appears to work in 3.6 IDE
add MassEditUMap
enable arrow keys and backspace for UScoreView QT

requires wslib update
implement .isUMap

for easyer UMap detection
use UChain duration also for UMaps
load UMaps at ULib:startup
add envelope, line, sine UMapDefs
replace 'isKindOf( UMap )' by isUMap in UGUI
U:valuesAsUnitArg, called at prepare and UGUI init
UGUI viewNumLines can now cope with argSpecs == nil
enable mass edit for UMaps

not flawless yet, but basically works
add remove method to richbuffers
solve argSpec compileString in case spec is nil
add CleanDragSink

to be used maybe in Qt
massedit nested UMaps correctly
remove 'remove' method from UMap and richbuffers
solve memoryleak for buffers, EQ and UMap

these UnitArgs now only know their parent unit when it is actually
playing. This prevents a buildup of units in the dict.
correctly dispose of synths of the UMaps in NRT