[hrplib/hrpCollision] enable to bypass normal vector correction

[fkanehiro]

This PR enables to bypass normal vector correction in hrpCollision.
The normal vector correction sometimes remove normal vectors to get better normal vectors for contact force calculation.
If it is disabled, hrpCollision can be used as an usual collision detection library.

[fkanehiro]

@orikuma
Please try this.
The normal vector correction function can be disabled by calling ColdetModelPair::enableNormalVectorCorrection().

[fkanehiro]

@orikuma
What do you think about this?

[orikuma]

I prefer this change but I think we need to update dpkg to pass travis before merging this PR.
(cf. #143 ).