Added AMD support

To use in an AMD project, load the module defined in raphael.amd.js. 

The existing rapahel.js file works the same as always, exporting a global Raphael object. You'll have to build it again using the make script. I moved eve.js to a subdirectory called eve. Other than that, I think the make script should work out of the box for you.

I removed raphael.js and raphael.min.js from source control since they're built by the make script. I would suggest adding those to the Downloads list on Github. 

Please let me know if you have any questions about AMD or what I did here. Thanks for building this awesome library!