add fetch/merge to update current local session with data previously saved on server
lame solution to an outofboundE in lines merging
Rename a challenge from Bill Kerr to credit the author
Don't even compare the worlds when there was a compilation error
Edit BatWorld's python template to correctly check the winning conditions (fix #309)
Merge pull request #345 from oster/fix-bat-world

Fix BatWorld::check() in python templates
(fix #309)
fail fast
give the amount of parameter for each templatePython
cosmetics
automatically refresh translations
Release 2.4.7

  Python is usable again, sorry for the inconvenience.

  * Engine:
    - Don't even compare the worlds when there was a compilation error
      Prevents python code from failing after reaching the solution.
  * Worlds:
    - Turtle: Merge lines that are in line with each other before
      comparing equality. You can now walk half of a segment, the half
      will be removed. You can walk to your destination in large
      amount of very small lines that are all depicting a long line,
      parts will be merged together. I hope that now, that damn
      world equality detection will not return false negative anymore!
      This fixes #338 and #339 (which are not exact duplicates).
    - Turtle: Show the superflous and missing shapes when the amount
      of shapes does not match.
    - #344 Turtle: Display the coordinates of the mouse.
      That helps reading the differences between worlds, if any.
    - #309 Bat: Edit the python template in order to test correctly
      the exercise's winning conditions instead of passing it.
  * Pedagogical content:
    - #341: French typo
    - TurtleArt: rename challenges from Bill Kerr to credit the author.
      http://billkerr2.blogspot.fr/2009/08/40-maths-shapes-challenges.html
skeleton of a new lesson on recursive strings
Give the parameter types to BatExercise::templatePython()

I sometimes need to convert these parameters from the java world to
the python one, and I need to know when that's needed.
show the scala compiled code when debug is enabled
properly deal with List[Int] parameters in templating exercises
first working exercise for the recursion.cons lesson
add the recursion.cons to the picture
deal with the logos of the new world and lesson
display executed code in debug mode
rename to match the name used in Python