remove stopIfFault from Demo code and put in library

[photodude]

Function definitions belong in the library (even if they work from the code)

[ryantm]

Hi, @photodude

Thanks for your contribution. I'm not that excited about putting a blocking method like that into the library interface. Generally, people should be handling errors and trying to recover or do some additional shutdown. This change goes somewhat in the opposite direction.

Also, it adds a configured serial port as a dependency to the library, when not everyone might want that.

Ryan

[photodude]

Thanks @ryantm I can see the points not to move that function into the library.