JUnit support for testsuite as root node

[bryanbcook]

As per #46, there is some variance in JUnit reporting implementations. According to this schema, JUnit can support a list of testsuites or testsuite as the root node:

Existing format:

<testsuites>
   <testsuite>
     <testcase/>
     <testcase/>
   </testsuite>
   <testsuite .../>
</testsuites>

Also supported:

<testsuite>
   <testcase/>
   <testcase/>
</testsuite>