Add support for 'count' option

This adds support to only count the number of scenarios by setting the
'count' argument to true.
Add support for 'debug' option

This adds support to wait for a debugger to attach at instrumentation
start. 'debug' can either be set to true or a number which represents the
timeout in milliseconds. Default timeout is 10 seconds.
Add support for 'coverage' option

This adds support to generate EMMA code coverage reports when using
CucumberInstrumentation. It is pretty much a 1:1 copy from
InstrumentationTestRunner.
Add support for 'log' option

This has the same effect as providing the Cucumber option '--dry-run'.