Throw exception when the user tried to do things that aren't supported

[stianlagstad]

Hi!

Thank you for this library. It would be nice if things that aren't yet implemented could throw an exception stating that they are not yet implemented.

An example: When I try to fetch a log object from a v1.4 WITSML server, then after getting the data successfully on this line (https://github.com/hashmapinc/witsml-client/blob/dev/src/main/java/com/hashmapinc/tempus/witsml/client/Client.java#L296), no parsing is done because convertVersion (https://github.com/hashmapinc/witsml-client/blob/dev/src/main/java/com/hashmapinc/tempus/witsml/client/Client.java#L726) does not support 1.4. Rather I end up on this line (https://github.com/hashmapinc/witsml-client/blob/dev/src/main/java/com/hashmapinc/tempus/witsml/client/Client.java#L298) and am returned null. It would be much better for me as a user to be notified of the fact that this is not yet supported. :)

Thanks!