mono/xwt — pull request #359 by sevoku (2014-07-16 08:35:38+00:00)
Title: Add color selector backends

This PR optimizes the default xwt based ColorSelector backend and adds a native GTK ColorSelector.

The defaut backend contains following optimizations:
* fix HSL conversion (H is degree and the others in percent and not 0-255)
* replace text entries with spin buttons
* add alpha slider
* raise ColorChanged event