GGS.styl: updated to v1.01

Also added some blank lines, so that most selectors and comment-banners have the same line numbers as `GGS.less`.  (Makes it much easier to keep the styles in sync!)

Fixed bug: restored colon to `#twoway .wrapperfirst-child`

Also restored colons to several comments.  (Looks like a search-replace bug that slipped through the cracks.)
GGS.styl: Removed vendor prefixed properties that aren’t in `GGS.css`
GGS.styl: Don’t use commas with newline-style selectors
GGS.styl: Prefixed variables with `$` for easier identification
GGS.styl: Refactored out baseline grid zooms and resets
GGS.styl: DRYed lots of code with factored-out functions