Some javadoc updates.
Changed DefaultResolvedComponentResult.toString() to delegate to the  id's getDisplayName().
Added ExecutionFailure.assertHasResolution() to verify that the failure has the appropriate failure resolution and use this in a couple of int test instead of hard coded assertions on the error output.
Removed some special cases from build failure reporting:

- BuildExceptionReporter no longer knows anything about TaskSelectionException.
- DefaultExceptionAnalyser no longer knows anything about FailureResolutionAware.
- Changed LocationAwareException so that it is FailureResolutionAware, and just delegates to its cause.
- Changed CommandLineTaskConfigurer so that it does not include the cause error message in the TaskConfigurationException message.
Minor spec update.