Add unity web gl benchmark

Unity WebGLBenchmark. 
- All source code was added, so the benchmark is self-contained
- Some files we too big (one in particular would not even be allowed to by hosted on Github because size > 100MB). They we compressed and README was updated so make notice that and also instructions on how to uncompress.
We'll have to add these steps to the jenkins/run* scripts when we start running these automatically. That can be a follow on bug, or I can take care of it.