Include redundant links when calculate collision

[chiwunau]

This is to fix the problem discussed in #206

[k-okada]

@h-kamada please check if this PR is OK for you.

[h-kamada]

The code itself seems ok.

I faced the collision problem when I was writing about :start-grasp , stop-grasp method of *pr2*.
Currently :start-grasp is checking grasp by checking collisions of all gripper links. ( --> https://github.com/jsk-ros-pkg/jsk_pr2eus/blob/master/pr2eus/pr2-utils.l#L263-L272)

I forgot details about this , but I think the problem was that pqp-collision-check didn't work well if I used (pqp-collision-check *pr2* target).
So I tried to check whether I can use (pqp-collision-check *pr2* target) if I use this code.
But the original code also worked well (not knowing why).
So I couldn't check whether this code is ok for my problem.

[chiwunau]

In this PR (I and not quite sure about what is actually done behind, in GL level and there might be better solution),
collision models are basically attached to their ascendant link found in eus model link-list, so in this case gripper links are considered as wrist_roll_link.
which means (pqp-collision-check (elt (send *pr2* :larm :links) 6) cube) returns 1 in the picture below.
I also tested when gripper is open and it returns also 1, I guess it is because all gripper links are calculate as a single static solid object.
So the original code may be needed to specify only gripper tip links.

[k-okada]

@snozawa , @YoheiKakiuchi could take a look at this PR and check if we can import this code into irteus level