Added a basic grunt build system.  Generates two

output files in the `build/` directory, one minifies and the other
basically just concatenates.
Some documentation on the build system.
Added built files.  Some projects don't include their build, but

I think it is the right thing to do in this case.  Following the model
of three.js.
Merge pull request #8 from colinsullivan/build_system

integrating Grunt build system