Add an optional range from target test to the location_test

[JessyBarrette]

The location_test as of now tests the distance between successive positions which is a good test for a trajectory dataset like a glider or an Argo float. This is however limited regarding testing the actual location versus the expected location of a platform or profile as an example.

I'd like to propose adding three optional inputs to the location_test that define a target location (target_lon [degree_east], target_lat [degree_north]) and an acceptable distance from the target (target_range [m]). target_lon and target_lat can either be a single value or an array the same size as the lon and lat inputs.

The location_test would output a SUSPECT flag if the distance from the target is exceeding the provided target_range.

As an example, such location_test can be useful to test:

• The location of a profile versus a predefined station location
• The location of buoy versus its deployment location

Although not necessarily considered to be used that way, it could also potentially be used to compare a mobile platform trajectory versus a predefined trajectory.

#46 present an implementation of the description above.