Changing file names, READMEs.

renamed:    libraries/Pulses/README_periodics -> libraries/Pulses/README_periodics-TODO
modified:   libraries/Pulses/README_pulses
deleted:    libraries/Pulses/README_pulses_0
renamed:    libraries/Pulses/periodics.pde -> libraries/Pulses/pulses_scratc
Preparing pulses_scratch (was: periodics.pde).