add more options to 'reverse' WFSPathTransformer

it is now also possible to reverse only x, y, angles, distances,
positions or times
add function for UEvent:renderNumChannels

WFSCollider now automatically determines how many channels are needed
for file rendering. When no (or non-existing) previewMode is selected
it defaults to the size of the current speaker configuration, enabling
offline wfs rendering to file.
make wfsSimpleReverb Udef look better with unit packing
remove GlobalPathDict @resources from WFSLib:startup

because it is already in GlobalPathDict:initClass now
move WFSPointSpec edit button to right
solve crossfading for 'tunnel' setups
fix some issues in draw crossfades.scd example
correct WFSFocusDetector input for open setups

open setups are setups where one of the sides is not filled
correct draw wavefields.scd for open setups
use Buffer:uSendCollection for WFSPathBuffer

it is now possible to use writeAudioFile with paths that don't have a
.wfsPath file