Integrate dbfit and fitnesse wikidocs

This is related to #13 

* Make DbFit wiki docs auto-expandable by FitNesse (alongside the core FitNesse docs)
* Remove `-o` option from `startFitnesse` shell scripts. This way bundled FitNesse docs will be expanded and also DbFit docs will be expanded too when using `-d`. It's still possible to override this by passing `-o` argument to shell scripts.
* Modify DbFit wiki docs front page so that it includes reference to FitNesse core docs.