Removed Mac-specific exclusion.
Declared gems using Gemfile.
Added a Sass pre-processor.
Upgraded Ruby to version 1.9.3-p125.
Updated Ruby version for documentation server.
Added ImageMagick.
Added Bundler.
Upgraded LibPNG to version 1.5.9.
Moved package description to common location.
Switched ImageMagick instructions to use pre-compiled binaries; JPG/PNG dependencies were problematic.
Upgraded PHP to version 5.4.0.
Quick note about Xdebug incompatibility with PHP 5.4.0.
Restructured the project to move the source files out of the root folder.
Modified the Twitter and GitHub mentions.
Updated to latest gems.
Added the target OS X version in the footer.
Updated the guide for OS X Mountain Lion.
Updated intro for Mac OS X Mountain Lion.
Upgraged gems.
Updated warning at bottom of index page.