Ground truth pose screwed-up coord system?

I remove the hack that claims that it fix Stage's screwed-up coord system. But in fact is that hack that makes the ground truth wrong, so I need to amend in my app.
Maybe the hack used to fix something that has been lately fixed in the underlying stagelib. Or maybe I just misunderstood the problem.... feel free to just reject this pull request in that case.
Merge pull request #4 from tut-yury/master

Fixed tf (yaw component) for the base_link->camera transform.
Merge pull request #3 from corot/patch-1

Ground truth pose screwed-up coord system?
Changed default GUI window size to 600x400 (fixes a bug on small screens, which results in segfault or absence of font-rendered content).
Added velocity to ground truth odometry.