Support Halfspace through main [collision/distance/continuous collision] interface

[jslee02]

This pull request enables to use Halfspace through the main interface. FCL contains Halfspace shape and necessary algorithms for [collision/distance/continuous collision], but it couldn't be used through the main interface collide(~) because it's not registered to the corresponding function matrices. Here is an example code that prints warning messages and doesn't compute collision result for Halfspace.

Cylinder s(5, 10);
Halfspace hs(Vec3f(1, 0, 0), 0);
Transform3f tf1;
Transform3f tf2;

CollisionRequest request;
CollisionResult result;

// Following code prints warning message:
// Warning: collision function between node type 13 and node type 16 is not supported
collide(&s, tf1, &hs, tf2, request, result);

This PR resolves #57.

[jslee02]

It's fixed by 40a0caf.

[scpeters]

👍

[scpeters]

I didn't like the github diff colorization, so I used meld on my local machine, and it was much easier to see the changes. Nice work on generalizing the tests.

[jslee02]

Agreed, it's hard to see the changes in here especially when the changes are more than 1k lines. The tests are still long, maybe I could shorten more once I get more used to Boost Test Library.

I'll wait another one day for further comments.