rename k-core to kernel

 - pom.xml files point to kernel instead of k-core
 - test-kompiled/marker contains text "marker" -- the issue here was actually that *-kompiled is gitignored
- JarInfo.java will be adapted to not depend on the .jar name (next commit)
JarInfo adaptation
also the kernel pom

this commit should work
Update README.md
Revert "JarInfo adaptation"

This reverts commit 50eac19a6857662524860131dfea79601437f5dc.
the marker again
Merge pull request #1132 from cos/hotfix/rename-k-core-to-kernel

hotfix/rename k core to kernel
refactor io in smt prelude