send configuration settings in testConnection

[ms34me]

Hello: This is the first time I've used github to contribute to community.

I used this library on MCP3425. The non-blocking routines work, but weird stuff happened when I tried using them without sending the configuration bit first in setup(). That isn't abundantly clear during its use.

So, in preparation of me submitting a ReadLoop_NonBlocking.ino example code, this small change is needed.