Major change in the API and conversion engine

• Changed the conversion engine to be more extensible and less hardcoded based on conversion strategies. This should allow for easier adding of more color spaces, and also extensibility with custom color spaces.
• Removed the almighty ColourfulConverter and added new ConversionBuilder that builds a converter that you can use afterwards.
• Started using double[] and double[,] for vectors and matrices.
• Using more of the in modifiers.
• Replaced get-only properties on color spaces with readonly public fields.
• Removed range checking and range cropping during conversions.
• Added new Jzazbz and JzCzhz color spaces.

(work is still in progress, documentation isn't ready, and code isn't covered)