Merge pull request #1 from nooone/steer

3D steering tests with bullet
- Renamed WeightedBlender to BlendedSteering.
- Added support for open paths to the bullet test.
- Javadoc minor improvements.
- Minor changes and code cleanup.
Embedded isEnabled check into the new public method steer of the
SteeringBehavior class. Also, the abstract method calculateSteering is
now protected.
- Now behaviors use getters for the parameters maxLinearSpeed,
maxLinearAcceleration, maxAngularSpeed, and maxAngularAcceleration. This
way developers can easily override them and take their values from the
owner or any other source.
- Added default max accelerations set to positive infinite in
BlendedSteering.
- Improved some tests.
- Minor changes.
Refactored the way how developers can specify behavior-specific and
character-specific max values.  With Limiter they no longer needed to
override. Also, Steerable is itself a Limiter.
Added angular speed truncation and an important note.
LinePath takes Array instead of []. Possibility to re-create the path.