Pick the first test fingerprint for a given suite/class name.  Fixes #827.

This drops older code that picked a single fingerprint within a framework.
This commit ensures only one name is executed across all frameworks.
The precedence is the order that frameworks are declared in Defaults.scala.
JUnit should be last because it is common for specs tests to be annotated
  with @RunWith for Eclipse support.  If a distinct fingerprint is not
  picked, the test will be run by both specs and JUnit.
In addition to this main reason, result processing code assumes one result
  per test class name and would have to be fixed if multiple fingerprints
  were allowed.