As explained on issue #26, this is complete driver revision

That's why I pull it on indigo_dev (@ipa-fmw , by the way, should not we follow the indigo-devel convention?). So it fixes almost all open issues:

 * Issue #28 : onNewColorSample and onNewDepthSample really slow. Now runs at the configured frequency of 25 HZ (without pc filtering)
 * Issue #26 : Publish depth image and camera info. I included also grayscale image, useful for calibration
 * Issue #25 : Image is wrongly formed
 * Issue #4 : rename image topics. I call them
  * rgb/image_color
  * rgb/image_mono
  * rgb/camera_info
  * depth/image_raw
  * depth/camera_info
  * depth/points

As l also ROS-formatted the code, the merge looks quite scary, sorry for not following the 1 change - 1 PR convention. But as it looks that people is using hydro branch, I don't see any problem on merging it on indigo, so people can compare.

I included recent PR #27, but didn't thoroughly tested, so please, @jordi-pages... give it a fast try.

Finally, I renamed parameter minNeighboursInRadius as min_neighbours to respect parameters naming conventions.

So when trying, don't be surprised if something doesn't work at the first try... But the global improve worth the migration.