Tab completion for jmh parameters

[jrudolph]

I started working on this here: https://gist.github.com/jrudolph/70d7cfbdff4086f78ee354408330ef7b

In that form you can copy the file to your project folder and it offer a new task jmh:runny that has tab completion inside of sbt. Not all options are supported yet but it features smart completion for benchmarks and matching parameters. I didn't manage so far to actually make it work under the jmh:run task directly.