minor doc fixes
fix gamut checks
add a few common lighting definitions
add method to determine boundaries

Performs binary search in freely defined color spaces. This
is useful e.g. to max out the gamut.
add palette optimization routine
add CSS and HTML color helpers

...also fixing a problem with out-of-bounds values in ARGB.
Now these are clipped before ARGB encoding.
remove remnants of clone support

based on the reasoning that no support is better than fake support.
add convenience ctor to ViewingConditions
fix color mixing implementation

by providing both valid mixing methods and documenting their
differences.
improve some docs
support unclipped CSS colors
support HTML/CSS color parsing
move custom atan to MathTools
add polar blending in perceptual correlates
add JCh hue-linear blending
add examples
add a bit to the README
update pcolor version to 1.2.0.0