MemoryError about rl-robot

[angelmtenor]

Yes, it's a problem when learning a task with too many states in a system with not enough memory. Wander 12K has 12500 states, requiring more than 7GB RAM when preprocessing the QBIASSR algorithm at the beginning (not detected in 16GB system). You should try tasks with fewer states.

To solve this issue I added some code to check if the system runs out of memory. I also changed the default task back to Wander-1K.

Tested in 4GB system.

Thanks!