Fixes to hover preview color RegExp

The RegExp is difficult to diff, so here are my changes. I made 3 changes:

1. For #3454, add "1.0" list of possible to alpha values for rgba()/hsla().

2. For #3455 The hsl()/hsla() functions now accept integer up to 999 (degrees) for the first parameter. According to the spec (http://www.w3.org/TR/css3-color/#hsl-color), "As an angle, it implicitly wraps around...". It would be easy to add more digits, if desired.

3. I noticed that zero or one space chars was accepted for optional whitespace (" ?"), so I changed it to zero or more whitespace chars ("\s*") to be more forgiving (and accurate).