Removes redundant custom mixins

Mixins now included in Compass 1.0
Resolves style inheritance issues

.front a {...} overrides a lot more than needed. It is made more
specific.
Adds/converts some comments

Adds headers for each partial, and converts most one-line comments that
were using SASS version to use CSS since it is more appropriate.
Changes gutter position

Gutter position is changed to the default 'after' to reflect SUSY one,
and avoid any consistencies that might have happened with 'split'
before.
Compass compile
Disables CSS3PIE Library

Turns off the library in the theme settings as it is no longer supported
in the Compass distribution.