Merge pull request #3 from ayrton04/master

Updating ekf_template.launch to reflect new parameters and cleaning up sensor configs
Fixing small bug with differential updating (introduced since last release)
Fixing small bug with differential updating (introduced since last release)
Adding new bag testing node and first bag regression test for robot_localization. Also adding a bag for testing.
Fixing differential integration of absolute pose information
Implemented message filters for ensuring transform availability. Also did some small code cleanup for safely obtaining transforms.
Adding new tests and new dependencies for package.xml
Merge pull request #4 from ayrton04/indigo-devel

Merging indigo-devel into master
Merging changes from master into hydro-devel