Get rid of mst_common

[Mr-Anderson]

Currently the only thin mst_common is used for is for holding the message files for Midge. To fix this the message fill will have to be relinked and the file dependency changed in Midge and MST_Control. While doing this the Midge message should also be changed to the gpsd standard specified in ROS documentation.

[jpeg]

May be better to use another GPS sensor instead for the new robot and dump the Midge IMU message completely.