add back jruby, as jython uses it for POSIX functions
Port the LoopDoWhile exercise to Python

- present this as another easy exercise on loops
- Also, make it a bit more interesting in java by having a buggle
  moving forward on the first step even if it's already on white ground
really implement this in Python
do not call addProgLanguage manually, that's dangerous. write templates instead
add some missing functions to the Python bindings
Greatly sanitizes the binding situation

* Simplify and factorize a bit the code.
  For example it was stupid to have a container for the script's
  sources as we already have the source files themselves

* Use the binding's entity to compute the solution world.

  It proved difficult to allow the templating in python (with author's
  provided functions for example) while keeping this ultra crude hack
  of using the java code to compute the answer.

  The VERY BAD NEWS is that all python templates have to be made
  functional... I am sorry about that, but I did not find any other
  solution.