New test reporter: JUnitReporter for JUnit XML output

usage: `venus run -t tests -e env -r JUnitReporter -o output.xml`

The test results will be stored in the file output.xml
Merge branch 'junit_reporter' of github.com:sethmcl/venus into sethmcl-junit_reporter

* 'junit_reporter' of github.com:sethmcl/venus:
  New test reporter: JUnitReporter for JUnit XML output

Conflicts:
	.venus/templates/default.tl