Fix JDBC and Resmon NullPointers

If we got null back from DB when using auto types, we would generate a NullPointerException when attempting to decode it as a number, so... lets just not try to decode a null shall we.

Then, once we passed null through, ResmonResult would die on a NullPointerException as well, so init the value it is going to print to the special [[null]] string and only set the actul value if it isn't null.