Merge pull request #1 from jdonaldson/master

Use base color class ( a concrete class) rather than an interface
added toColorAlpha
added toCss3/toCss3Alpha,reimplemented ColorAlpha
added clone to Color

ColorAlpha can only be instantiated by a non-alpha instance
remove null argument check

it is no longer required since ColorAlpha can only be created from an
instance
removed alpha classes
rename of methods and classes
renamed classes and methods to Haxe standard (all acronyms capitalized). Also changed Rgb8 into RGB and Rgb64 into RGBHR (high resolution)
added more (empty) tests
color parser infrastructure and parsing for CMYK
refactoring
fixed string format
renamed RGBHR to RGBX and more string format
renaned RGBHR to RGBX in classes
one more test (failing)
more tests for CMYK
removed IRGB
added parse and removed TestConvert
fixed issues and added tests
fixes
added Grey color space