-------------------------------------------
switch variable: $colscale -- funct color scale
-------------------------------------------
switch value: 4 => two-cond red-grn (complex data)

This color scale designed for two condition,
phase-analyzed data (standard OFF/ON design).
The first half of the phases (correlated with
the odd stim) are colored grn and the second half
(correlated with the even stim) are colored red.
A *positive* angle_offset cancels a delay in
the functional signal.
