Write Cucumber test results to disk.

[jimCresswell]

Gulp-Cucumber does not return the test results as a stream, nor does it have access to them, Cucumber-js by default just writes the results to stdout.

There are intentions to add custom plugin support to Cucumber-JS which may allow Gulp-Cucumber to pass a stream based reporter to pass through the results.

In the mean time, it would be possible to invoke Cucumber via Gulp on the command line and pipe the results through cucumber-junit to disk.

[jimCresswell]

This is done. The files are in JSON format, if we want XML we'll have to do something with #56 .