New method setColor to set current color silently (#21)

Palette property is now editable (#17 ).
New methods show(), hide() and toggle() (#13 )

New canvas size options

Merge from #8

Merged #8

Fix #7
Removed unused DOM elements

new method AColorPicker.from()
new method AColorPicker.parseColor()
new option useAlphaInPalette
testing with mocha

Alpha channel in color palette