fixes some frame logic issues caught by trying:
```
terrain = RigidBodyManipulator(['sdf/drc_practice_task_',num2str(task_number),'.world']);
x0 = Point(getStateFrame(terrain)); % all zeros
v = terrain.constructVisualizer();
v.draw(0,x0);
simulate(cascade(terrain,v),[0 5],x0);
```
ignore self collisions
Merge pull request #651 from avalenzu/master

Make rospack check for package.xml
Merge pull request #654 from RussTedrake/frame_fixes

Frame fixes
clean up link/joint name access function.  index => id.  resolves #182
updates the existing code to the new function names.
joint names are no longer automatically changed to be unique.  i print a warning if they are not unique inside a single robot, otherwise the robotnum is sufficient to distinguish them
resolves #615
Merge pull request #657 from RussTedrake/taylorvar

resolves #615
add yalmip pod logic to checkDepedency
Merge pull request #661 from RussTedrake/yalmip

add yalmip pod logic to checkDepedency
add check dep for gurobi
Merge pull request #663 from RussTedrake/yalmip

add check dep for gurobi
Merge pull request #656 from RussTedrake/findlink

Find link
Merge remote-tracking branch 'upstream/master'
Merge pull request #16 from mitdrc/merge-master

Merge master