Added favicon and optimized GA script from H5BP.

Not sure why/how the .md data is changed.
Added SVG icons

I also ran the old png icons through imageoptim which greatly reduced
their filesize.
Most of the icons are from thenounproject. I added an
`attributions.html` file with the attributions they ask for because I
wasn't sure what else to do with it.
Revert "Added SVG icons"

This reverts commit 05f5638aa06d90398e76ca6555978c3a4b5e4475.
Revert "Added favicon and optimized GA script from H5BP."

This reverts commit 9347f4899d107458243f9bd854890c400990e234.
I didn't change anything in these files, but it thinks I did...
Merge remote-tracking branch 'upstream/master'
Optimized async scripts.

See http://css-tricks.com/thinking-async/ or the html5 boilerplate project for more info.
Added favicon
Merge pull request #3 from Vestride/favicon

Add Favicon