Fix some color names (prefer gray over grey) and fix some typos in the color name hex mappings.
Attempt to replicate the sass 3.2 behavior regarding color formatting.
Merge branch 'master' into feature/colors
support colliding CSS filter effects functions

CSS filter effects [0] define several functions (invert, grayscale,
opacity, saturation) that collide with the names of built-in Sass
functions. Overload these functions with a no-op when the filter effects
function signature is discovered. This is compatible with Ruby Sass.

For example, calling `invert` with a color will return an inverted color
as before:

    color: invert(#333) => color: #cccccc

But calling `invert` with a percentage will pass through the function
call unharmed.

    filter: invert(30%) => filter: invert(30%)
    filter: invert(.03) => filter: invert(.03)

Fixes #151.

[0]: http://www.w3.org/TR/filter-effects/
prefer "gray" to "grey" when converting colors to names

For consistency with Sass.
inspect: always round color channels before inspection

Since RGB channels are stored as doubles, HSL/RGB conversions can result
in decimal values being stored for a channel. This breaks color name
lookup. For example, previously

    rgb(127.5, 127.5, 127.5)

would fail to be converted to "gray," despite being rounded and output
as

    #808080

which *does* map to gray. So instead of performing the rounding only
when outputting as a hex triplet, perform the rounding at the start,
always. This achieves consistency with Sass.
call function
Merge pull request #517 from wonja/call_function

call function (Fixes #418) it works I seen it with my own eyes
Merge remote-tracking branch 'upstream/master' into feature/colors
Merge pull request #515 from benesch/filter-effects-functions

support colliding CSS filter effects functions
Now targeting sass 3.4.4 behavior for color format.
Merge remote-tracking branch 'upstream/master' into feature/colors
Merge branch 'DealerDotCom-feature/colors't push origin master
Interface: Teat source string as SASS.
Fixes #488.