Follow off chase off-trigger

still some glitches:
sometimes last pixel in chase elements stays lit
after the follow off chase is finished

some glitchy issues with overlapping trigger-on
have todo placed in trigger on for this.

No notion of different curve for off motion yet
another twinkle demo just for fun
minor refactor
Add reverse chase
changed twinkle note to clarify trigger use limitation
add first draft of color shift effect
remove unused stub class
cleaned up use of time_delta
make first time-delta correct at show start
time delta on show now, not on self
del comment
repair broken pulse after follow chase changes
use future division
remove dead frame_rate assignment
remove old preview mode stuff
return some logging to debug level
implement dynamic framerate
add OSC input interface
update examples to also use OSC