Report takes too long to parse for large codebases

[m1foley]

After I bumped the gem to 0.1.4, parsing the generated report went from 1 second to 11 minutes. It appears that #3 caused it to generate output for all test cases, which resulted in a 75MB file because I'm running it on a large codebase.

The "CI trending" reasons behind that feature seem valid to me, but I think large codebases need an option to be less verbose.

---

0.1.3 Bamboo output:

simple	04-Sep-2018 19:50:11	Generating build results summary...
simple	04-Sep-2018 19:50:11	Saving build results to disk...

0.1.4 Bamboo output:

simple	04-Sep-2018 19:15:57	Generating build results summary...
simple	04-Sep-2018 19:26:46	Saving build results to disk...

[macobo]

Also affected by this in a different way - CircleCI takes forever to parse the resulting file (on clientside no less), making this gem a bit useless when using with CI.

[m1foley]

My workaround notes:

The main gem generates an invalid report when all tests are passing: it contains testsuite but no instances of testcase. As a result, we couldn't enable JUnit parsing on Bamboo to tell us what the RuboCop errors were. The gem also has an issue (#18) in which generated reports are too large and take 10 minutes to parse.

The boltthreads/rubocop-junit-formatter fork (boltthreads branch) fixes the first issue and doesn't contain the code that led to the second issue.