Xctool merges similar testsuite objects XML trees

Referencing issue: #141
Xctool was not compatible with Jenkins because the XML output from
xctool had different testsuite objects with the same name. The XML tree
is now merged by testsuite name.
Xctool merges similar testsuite objects XML trees

Referencing issue: #141.
Xctool was not compatible with Jenkins because the XML output from
xctool had different testsuite objects with the same name. The XML tree
is now merged by testsuite name.