Benchmarking

Next Step! (c) 

I've build simple benchmarking system to provide us information about framework bottlenecks. Currently it uses NSLog to print all information about benchmarking results. Probably later we could try to hook up it to Travis CI output, but for now it seems complicated and unnecessary for several reasons:

1. Travis CI cannot run on iOS devices
2. Test results heavily rely on the hardware they are run on. I have no information on what Macs Travis CI uses and if they are the same.

I've tried to include all mapping scenarios into benchmarking, but if i missed some, it can be easily added to the mix( see EKBenchmark class). 

When we'll be evaluating our CoreData bottlenecks, benchmark will be very helpful, since now we'll be able to use Instruments Profiler to detect problems.

/cc @lucasmedeirosleite