Cleanup in preparation of catkinization.
Catkinize.
Update copyright, self import guard, and catkinize
PEP8, cleanup, and remove roslib
1.7.1
fixed build issues introduced in catkinization
1.7.2
Install xacro.py as a program so it can be run
1.7.3
Remove bin copy of xacro.py
Adding supoprt for substitution_args 'arg' fields
adding unit test for substitution args
backwards compatilibity with rosbuild
Merge pull request #6 from jonbinney/sub-args

Sub args
rolled back to last version that used rosbuild
merged in fixed xacro python code from hydro-devel

includes fixes for subsitution args.
merged in updated tests from hydro-devel