Merge branch 'media-queries'

- Fixes #31

* media-queries:
  Do not sample at fractional pixel widths
  Note the responsive feature in the README
  Handle media query width edges properly
  Prune empty selectors
  Highlight interval inclusion ambiguity
  Apply Josh's syntax fixes to new tests
  Include media queries in output
  Passing media query width tests
  Deprecate bookmarklet
  Output styles common to all media queries
  Save styles in callback so they are accessible to others
  Add underscore
  Disregard sub-pixel intervals
  Sample styles in each media width-interval
  Adjusting browser width does not affect max-device-width
  Calculate media-query width intervals with sample points
  Detect media-query width breakpoints
  Enumerate media queries
Handle percents (unicode?) in class names