Put linear-gradient in line with w3c spec

Just thought it'd be a good idea that the linear-gradients were in line with the [w3c spec](http://www.w3.org/TR/css3-images/#linear-gradients). There are some ramifications, namely, browsers that only supported one of the initial spec grammars that did not include the `to <side-or-corner>` syntax.
According to [Mozilla's MDN](https://developer.mozilla.org/en-US/docs/Web/CSS/linear-gradient), Firefox 3.6 -> 10 and Chrome 10 -> 26 would be affected.
IE 9 supports neither, 10 supports both, and 11 only supports the formal spec.
**Firefox:**
[Firefox 3.6 was automatically updated](https://groups.google.com/forum/#!topic/mozilla.dev.planning/H7jdpvT3Nbc) to version 12 on May 9th, 2012.
**Chrome:**
Chrome has had automatic upgrades enabled for as long as I can remember.
**IE:**
Since only v10 is affected only windows 7 and server 2008 are affected. If the user has been getting their Windows Updates, they should be on IE 11 now (which supports the formal spec) unless they [specifically installed something to disable the update](http://www.microsoft.com/en-us/download/details.aspx?id=40722).
**Safari:**
I have limited data on Safari due to being at the office right now. I can say that Safari 7 seems to support the formal spec though I haven't found any good docs with a version/support table that is up to date (the MDN table seems to indicate a nightly circa Safari 6, June 2013).