Reporting argument error

Given I have pygments, bcat, and rdiscount installed
When I ran my cucumber features with ARUBA_REPORT_DIR=doc
Then I received an ArgumentError from inside lib/aruba/reporting.rb

I poked around the history of ```SpawnProcess``` and ```Reporting``` to try and confirm that you dropped the ```filter_ansi``` flag support, seems so.

I suppose this'll take more work to make Travis happy...