Reduce launchfiles

Eliminate editor detritus, and also unnecessary "with sensors" launcher.

There is presently a problem running this due to a missing file (husky_with_sensors.urdf.xacro) in husky_description. Please avoid merging until that problem is also resolved. 

In the near term, we should also eliminate unnecessary duplication and nesting in the xacro files by taking advantage of conditional blocks:

http://wiki.ros.org/xacro#Conditional_Blocks