Merge pull request #195 from Adirelle/RegisterUnitEvent

Use RegisterUnitEvent to replace our home-brew event dispatcher.
Merge pull request #196 from Adirelle/heal_prediction_frequent

healprediction: add a .frequentUpdates option.
Merge pull request #197 from Adirelle/classicon_cleanup

Reduced copy-pasta in classicons.
Merge pull request #198 from Adirelle/hide_on_disable

Hide on disable
Merge pull request #199 from Adirelle/altpowerbar_tweak

Altpowerbar tweaks
Merge pull request #200 from Adirelle/color_gradient

Provides a color gradient based on hue/chroma/luma (HCY').