apexq: add support for panel color shifting based on a sysfs interface

Adapted from work by morfic and ktoonsez and invisiblek

Creates a sysfs interface here:
  /sys/class/lcs/panel/panel_colors

Will accept 0-4 for parameters:
  0 - Cold (more blues)
  1 - Cool
  2 - Normal (stock colors)
  3 - Warm
  4 - Hot (more reds)

PS2: whitespace error correction

Change-Id: I457504ba2c7bd966e5c21767c769d0d637284ea4