Fix problem with rotated meshes.

The problem was that assimp rotates collada files such that the up-axis (specified in the collada file) aligns with assimp's y-axis.
Clean up one function inside of the URDF loader
DRY build process
Deprecate World::getRobot() and getObject()
Merge branch 'master' of github.com:golems/dart
Added the other joint types for root
Merge branch 'master' of github.com:golems/dart
Fix collision checking problem caused by 5136748a062d025092a2d9268ee00efafed3d5bf
Fix compiler error on Mac
Set version 2.4
Changed patch version number
Remove color hack in primitive rendering

Lighting was fixed in grip.
Merge remote-tracking branch 'origin/master'
Fix #48: Fix Jacobian calculation for joints with both static and variable rotation transforms and for joints with an arbitrary-axis rotation transform
Merge branch 'master' into sensory