Checking for sonar version - M750D compatibility.

[ChristianWesterdahl]

In the file oculus_sonar_node.cpp, line 172 to 177 you check for the part number of the sonar, throwing an error if it is not that of the M1200D sonar.

Why do you do this check in a wrapper for a driver that supports multiple sonar models? We are attempting to use this code with an M750D - can we simply remove this check? Or would we encounter problems?