Java backend: implemented the Matchable interface
Java backend: implemented the pattern matching functionality which is independent from the unification
fixed an incompatible type error detected by Eclipse
Java backend: more progress on the interface for pattern matching
Java backend: cleaned up PatternMatcher a little bit
Java backend: experimental: more work on lazy substitution and evaluation of the subject term during pattern matching
reverted my previous commit
Java backend: fixed a bug introduced by me earlier in the visitor pattern
added mockito to the Eclipse classpath file of KTool