Sensor Interfaces.
I re-wrote th INS_Board driver to use an interface defined in motioncalc.go.
This interface allows a factory method to parse the new json config file, and
fork a go routine for each sensor.
This has made the code simpler, and set a heirachy of dependancy.
However I am still not 100% happy with my naming pattern, this may need some improvement in future.

	modified:   ins_driver.go
	modified:   motioncalc.go
	modified:   navicomp.go
	modified:   tcpComs.go