add a sprite helper function
Merge branch 'stable' of git://github.com/chriseppstein/compass into stable
add sprite-image-position test
Add missing semicolon in @function relative-unit
Add rem output with pixel fallback including additional under-the-hood changes.

- Add support for outputting rem units with pixel fallbacks.
- Add units partial with rem() mixin and convert-length() function
- rem is a flexible mixin for using rem units
- convert-length is a general purpose function for converting css lengths between units
- Use convert-length for unit conversions in vertical-rhythm
- Clarify allowed units
- Add rhythm-margins and rhythm-padding mixins
- Add support in rhtyhm borders for border-color
- $font-unit is replaced by $rhythm-unit
- $relative-font-sizing is now @private and derived from $rhythm-unit
Move vertical_rhythm import to after config variables are set.
Round rem pixel fallback values to nearest pixel, fix double font-size output in establish-baseline, add additional tests

- Pixel fallback values for rems need to be rounded to the nearest pixel during output
- Don't run font-size declaration through output-rhythm in establish-baseline (prevents double declaration).
- Add compiled css for _units.scss to fixtures so that tests pass.
- Add additional test for px unit output for _vertical_rhtyhm.scss
Rhythm-border mixins now output border-style after border-width; change test css to match so it passes.
Added tint() and shade() color helpers,  including documentaiton and tests
[documentation] Fix references to the hyphenation module. Closes #918.
Missed this hyphentate.
Merge pull request #866 from kwliou/stable

add a sprite-image-position() helper function
added catch in ChunkyPng engine to detect invalid png images closes #860
Added CSS3 filter() mixin
Adjusting the multi-column mixins to match the spec for column-rule-color, column-rule-style, and column-rule-width (the implementation was missing the critical "column-" prefix).
Replace Heroku add-ons site with Heroku status
Merge pull request #939 from mschoening/stable

Replace Heroku add-ons site with Heroku status
Revert "Merge pull request #866 from kwliou/stable"

This reverts commit f562f4855d1e290ac70605063f096a473af4bb5c, reversing
changes made to 237853a94489534e9902272808bc588b74c65ed0.

This merge broke the code and once fixing that, the tests didn't pass.
Merge branch 'stable'
Merge remote-tracking branch 'parkr/stable' into stable-filters