Use the new coffeescript's 'register' to prevent global state change

Since requiring coffee-script changes require.extensions globally,
cloudinary would overwrite a project's coffee-script compiler with
it's own version which could lead to version incompatibilities.

The new coffeescript has an explicit register function which takes
this into account allowing multiple coffeescript compiler versions.
Merge pull request #16 from edgecampus/master

Use the new coffeescript's 'register' to prevent global state change