Switch to modularized parser combinators 1.0-RC2.

With Scala 2.11.0-M5, the parser combinators are now a separate module.
I'm publishing 1.0-RC2 now, and verified scalacheck compiles against it:

```bash
sbt12 'set version := "1.10.1"' \
'set scalaVersion := "2.11.0-M5"' \
'set every scalaBinaryVersion := "2.11.0-M5"' \
publish-local
```

Could you please release a release of 1.10.1 against 2.11.0-M5 using this PR?
That way we can publish partest. /cc @gkossakowski