redding/assert — pull request #173 by kellyredding (2013-12-30 20:54:00+00:00)
Title: only display ANSI styled output if the view IO is a tty

This updates the view to know whether it is a tty or not and only
display ansi styled output if it is a tty - regardless of any other
config settings. This is to be a good citizen and not output ANSI
style coded output to IOs that don't know what to do with it.

Closes #172.

@jcredding ready for review.