Update tutorial

[[e-mail]]

We need to update the tutorial to match the current source code. I created two cases: tutorial/gridworld.py and tutorial/pendulum.py so that no major code changes are necessary.

[[e-mail]]

pretty much done. It is already online at http://acl.mit.edu/rlpy Could some do a proofread on this? If someone has read over it, we can close this issue

[Robert Klein]

Fixes #8. Fixed incorrect filenames and references to pendulum.

→ <<cset d0e3cbe5dae1>>