+Packaging and distribution
+-Add to README.txt a "Contributors" section and/or a "Thanks also to" section to list the names of people who’ve helped.
+Code structure (modules and packages)
+-convert sensors module into a package
+-rename Simulation.get_joint as get_sim_joint
+-make JointSensor.__init__ be able to receive a Joint OR a SimulatedJoint, which
+wraps a Joint. The idea is to avoid confusing calls such as "x.get_joint().get_joint()"
+-move ./tests to ars/test and convert to a package? See
+-dBodySetFiniteRotationAxis. is it necessary to set this if dBodySetFiniteRotationMode = true?
+-rename package "model" to "core"?
+-move tests in utils.mathematical to a test file
+-create a subclass of vtkInteractorStyleTrackball (http://www.vtk.org/doc/nightly/html/classvtkInteractorStyleTrackball.html)
+-remove the event bindings for this class which interfere with the desired behavior
+-see VTK/Tutorials/InteractorStyleSubclass (http://www.vtk.org/Wiki/VTK/Tutorials/InteractorStyleSubclass) for ideas
+-for a plane use a PlaneSource instead of a slim box
+-draw joints: use a point for the anchor, and an arrow for each axis
+-use the position argument to create Axes object
+-store joint rotation limits and resistive force factors
+ from PyQt4 import QtCore, QtGui, uic
+ # Create a PyQt window using a .ui file generated with Qt Designer ...
+ application = QtGui.QApplication(sys.argv)
+ window = uic.loadUi("gui.ui")
+ vertex_slider = window.findChild(QtGui.QSlider, "vertexCount")
+ edge_slider = window.findChild(QtGui.QSlider, "edgeCount")