feature/new parser on kore

**please review** @dwightguth 

A bit of context:
take textual full K outer definition ( with KAST inner)
->
KIL outer + bubbles
-> via KIL-to-KORE
KORE outer + bubble
->
parse KAST bubbles with new parser using a KORE outer definition of KAST (from kore.k)
->
complete KORE :-)

@radumereuta, this is the work we did last week. I fixed some tests and cleaned up a bit. have a look and adjust as you see fit.
not really for these classes as we cannot extend them. Remember our discussion regarding implementation choices for the collection data structures. I went with the simple solution of leaving the pure Scala classes underneath and simply gave them a `stream()` and `iterable()` through `Collections` (there is also an `immutable()` method taking a mutable Java class and returning a Scala immutable class, and stream specialized stream collectors). This covers all basic needs and keeps things immutable and safe. I could implement our own Set and List classes so that we have better control over the interface, but it wasn't a priority. The only change would be changing the calling syntax you noticed, `.stream()` vs `stream(...)`, which is simple and mechanical and can be done at any later point in time.