Subtract class

subtract a signal and a number or a signal and a signal
handles summing two signals

or a signal and a number.
multiply handles two signals
min and max accept two signals
Greater than compares two signals
LessThan accepts two signals
Equal accepts two signals.
testing second signal inputs
Modulo small doc changes.
first Expr version

aggregate signal processing expression
bug fixes
handles multiple inputs
Expr testing
testing OR multiple inputs
refactored Expr

put regexp all in one place and function callbacks all in one place
more Expr tests
added Expr tests to list
rewrote floor in BitCrusher with Expr
noting Expr changes
using Chebyshev instead of phaser

phaser didn’t work well for this example