Exercise paced motion along a path

Add a test using animateMotion with calcMode="paced" for paced motion
along a path.
Merge pull request #65 from ewilligers/motion-path

Exercise paced motion along a path
Compare against natively paced motion

Correct test case animateMotion-paced.html so that one element is moved
using SMIL in JavaScript and the other element is moved using Chrome's
native SMIL implementation. Checking visually, the two elements move identically.
Merge pull request #66 from ewilligers/native-motion-path

Compare against natively paced motion
Allow 'none' and 'currentColor' for stroke, fill

'none' and 'currentColor' are valid values for the fill and stroke
attributes
http://www.w3.org/TR/SVG/painting.html#SpecifyingPaint

'currentColor' causes the color from the 'color' attribute to be used.

'none' means than no paint is applied.
Merge pull request #67 from ewilligers/current-color

Allow 'none' and 'currentColor' for stroke, fill