Add benchmark subproject.

Based on ideas from the scala-benchmarking-template
project on github. Uses google caliper.
Updated to scala 2.10.0.

Removed unfiltered/lift-json dependency in favour of spray-json,
which is up to date.
Switch to using scalameter for the benchmarks.
Basic normalization of accented characters.

Converts accented chars to [a-z] before matching.