update link to AMD definition

The previous link was going to a document retained for historical purposes.
The current link is where the definitive API and definition is kept.
Merge pull request #72 from billmag/master

Update r.js and require.js, add .erb processing to requirejs.yml.
Merge pull request #68 from Trevoke/patch-1

update link to AMD definition
Update to require.js 2.1.2
Merge pull request #6 from billmag/requirejs-2.1.2

Update requirejs, r, and almond
Merging in requirejs2.1.2 branch from gurdotan