Merge pull request #3 from timholy/master

More efficient distinguishable_colors
Import Base.isless
Some documentation.
remove deprecated functions and add needed import of isless

Conflicts:
	src/Color.jl
add method for setting source color with a ColorValue
link to CAT02, harmonize reference format, add reference links
Merge pull request #5 from waldir/patch-1

link to CAT02, harmonize reference format, add reference links
rename of set_source_rgb to set_source, since it is not RGB-specific
rename has to haskey
still need to import set_source_rgb to use it
parse_int to parseint
Define 'color(c::ColorValue) = c'
Refactor distinguishable_colors API
Fix chroma defaults (thanks D. Jones)
writemime function fors colors and arrays of colors
added (exported but previously missing) weighted_color_mean function, and linspace function to generate a linear color ramp
Merge pull request #8 from stevengj/master

added weighted_color_mean and linspace functions (linear color ramp)
eliminate deprecated @MIME
Fix xml header in writemime