first pass at making simulink optional for compiling
successfully compiles on a machine w/o simulink
height map terrain uses barycentric code.  working on integration with viewer, by writing obj files
littledog terrain demos work
updated terrain test examples in drake.  they look pretty cool now.  (but won't actually work in vrml for the moment)
fixed typo in flat terrain
cleans up obj and wrl file writing.  resolves #440 - except the normals are still pointing the wrong way
fix vrml terrain color.  giving up on normals for now.  the viewer doesn't seem to accept anything.
Replace collision_group_name with contact_shape_group_name

This makes it consistent with consistent with the contact_shapes property.
Rename old methods to getContactShapeGroupNames

RBM/getContactGroups and TSRBM/getCollisionGroups are now both named
getContactShapeGroupNames.

Resolves #408.
removing prints when solver fails over to gurobi
Add more grp support for getTerrainContactPoints.

Now you can pass a single cell-array of strings to use the same groups for all
bodies.
Don't check terrain collisions unnecessarily.

If specific groups are specified in `active_collision_options` and `terrain` is
not one of them, don't check terrain collisions.
Use active groups when checking terrain collisions

Pass the groups specified by `active_collision_options` into
`getTerrainContactPoints`
Update testActiveCollisionOptions.

Now we check both bullet (if applicable) and non-bullet (i.e. terrain_only)
collision detection.

Resolves #364.
Merge pull request #445 from kuindersma/silence-qp-prints

removing prints when solver fails over to gurobi
add missing dependency name to new error msg
Merge pull request #438 from RussTedrake/compile_wo_simulink

Compile w/o simulink
pulls writeOBJ out of RigidBodyHeightMap per Andres' request
Merge pull request #439 from RussTedrake/terrain

Major cleanup / update to RigidBodyHeightMapTerrain