Replace RRT function customizations with something similar to Boost's named parameters #86
Description
The current RRT planning variants are complex and difficult to understand. They also unnecessarily couple several orthogonal parameters. It would be a cleaner and more manageable interface to do something similar to Boost's named parameters. This is what the Boost Graph Library does, and it seems to work well (after an initial learning curve).
We probably don't need something as feature-complete as Boost's implementation, but we could imitate it.