Bug fix for sweep class, and updated to br255
Added MotorJoint, along with small refactoring of JointDef to require type
Merge branch 'master' into motor-joint
Bug fix for sweep class, and updated to br255
Merge branch 'master' into motor-joint

Conflicts:
	jbox2d-library/src/main/java/org/jbox2d/common/Sweep.java
MotorJoint fixes