Refactor DART. Lots of non-backwards-compatible changes.

- Remove Transformation classes. Their functionality is now included in joint classes.
- Add Featherstone algorithm. Can currently only be used without collision handling. The old algortihm is still present and used for that case.
- Remove kinematics namespace. Functionality is moved to dynamics classes.
- Add dart root namespace
- A lot of function and variable renames
- Add constraint namespace
- Some parsers, unit tests and apps have not been adapted to the changes yet and are therefore currently excluded from building.
- Add "common" namespace