Basic benchmarking for testing performace of processes

Run with `go test -bench=.`, produces an output that indicates how many nano-seconds it takes per operation.

Useful for testing the processing without any HTTP overhead.

eg. #97 

before:
````
BenchmarkGetHead          500000              4903 ns/op
BenchmarkGetHelm          200000              7291 ns/op
BenchmarkGetBody           50000             30597 ns/op
````
after:

````
BenchmarkGetHead         5000000               631 ns/op
BenchmarkGetHelm          500000              3089 ns/op
BenchmarkGetBody          100000             14853 ns/op
````

(awesome result!)