Configuration: add reporter parameter
SuiteResult: add successes list
Add XMLJUnitReporter

Just the minimum to be parsed by Jenkins CI.
XMLJUnit: example of use
SpecNode: add action to summarize the results

The #summarize action reduces the results (and reasons) to the most
meaningful one, and returns a new SpecNode, so that the original is
preserved.
SuiteResult: allow traversal of contexts/examples
XMLReporter: refactor the report creation

Change the name of tests reported to include context information.
Merge branch 'xml_reporter' into 0.5.0
Bump version to 0.5.0
SuiteResult: change variable name to non-reserved
manifest: include XMLJUnitReporter in the package
Merge branch 'xml_reporter' into 0.5.0
Merge branch '0.5.0'