Throw IllegalArgumentException when long-deprecated Runner args -r, -c, or -p are used
Use new arg letters internally in Runner for old -r, -c, and -p args
Update to use ScalaCheck version 1.12.1
Update releaseVersion from 2.2.3-SNAPSHOT to 2.2.3
Merge branch 'fail-rcp-args-in-runner' of https://github.com/gcberger/scalatest into 2.2.x
Bumped rev to 2.3.0-SNAP1.

Conflicts:
	project/scalatest.scala
Fixed conflict when pulling the -c, -r, -p deprecation expiration for Runner
as well as the upgrade to ScalaCheck 1.12.1, all pulled from 2.2.x branch.

Conflicts:
	project/scalatest.scala