actually wanted to start with RexEvaluation for projection, but then worked on the JDBC support
more again on the RexExecutor
started adding a kinda-test framework. Codegen is getting somewhere
shipping of compiled janino code with custom classloder is working
its pretty much working
Testcases run seperatly [ci skip]
problematic corner case
added some more tests for string-based Rex, renamed test table [ci skip]