Added a package for the sensor processing part of the core system
core_sensors_ir node now allows user to specify which channel to use on the Arduino, and it publishes on a topic named properly. It's just publishing the raw data for now, but it should be easy to add the mapping function from raw to cm.
Merge branch 'master' into sensor_IR
Placed odometry node inside core_sensors package.
Added polynomial for the IR data conversion