implemented proper scaling.  resolves #603
checked my own algebra and found one typo
fix frame logic bug caught by Sam Calisch in class with the following test: To recreate the behavior, it's enough to go into examples/Acrobot/runPassiveURDF.m and add this line: p = p.addRobotFromURDF('Acrobot.urdf'); after the original creation of p. Then later, change randn(4,1) to randn(8,1) to create initial conditions for the two acrobot system.
change the joint_limit_min and max stored in RigidBody after we call setJointLimits in RigidBodyManipulator
resolves #613 and adds a test case
Merge pull request #610 from hongkai-dai/fix-joint-limits

fix setJointLimits
Merge pull request #606 from RussTedrake/inertiaEllipsoids

implemented ellipsoid scaling with equivalent masses.  resolves #603
add warnings if some rows of the gradient matrix is empty in NonlinearProgram
add documentation to solve function in NonlinearProgram, for info 11 and 12
fix a typo
fix the English
add robustness to different shape inputs
Fix the documentation for INFO 11 in NonlinearProgram, add more print out message if INFO 11 is returned
Merge pull request #614 from RussTedrake/spring_no_damper

resolves #613 and adds a test case
Merge pull request #616 from hongkai-dai/add-NonlinearProgram-warning

Add nonlinear program warning
Merge pull request #607 from RussTedrake/frame_logic

fix frame logic bug caught by Sam Calisch in class