add scala nature and files

 - add kore module to the mvn build system, make kernel (and only kernel) dependent on kore
 - add Scala KORE classes
kernel depends on kore
Merge branch 'hotfix/rename-k-core-to-kernel' into feature/scala-module
refactor io in smt prelude
Merge pull request #1135 from dwightguth/smtprelude

refactor io in smt prelude
Merge pull request #1131 from cos/feature/scala-module

add Scala KORE inner classes