Making the testing Sqoop cascades easier

Got rid of setting MapRedHome in the Cascade
Extracting out the Database specific piece.
Providing a fixed function for data setup and cleanup
Not sure about `AroundExample`, but note that if you extend `Fixture` you can do things like apply the trait to individual tests, and pass in some unique values to each test which they can use to set up a unique environment without stepping on the toes of any other test using the same fixture that  is running concurrently.

How useful any of that would be to you, I don't know ...