(GH-151) Implement whitespace checks for markdown
(GH-151) Implement whitespace checks for markdown

This implements a rake task check:trailing_whitespace. The actual check
has mostly been written by Garrett Honeycutt.

Co-authored-by: Garrett Honeycutt <e6fb06210fafc02fd7479ddbed2d042cc3a5155e@garretthoneycutt.com>

dhoppe/modulesync_config,dhoppe/modulesync_config,voxpupuli/modulesync_config,dhoppe/modulesync_config,voxpupuli/modulesync_config,puppet-community/modulesync_config,dhoppe/modulesync_config,voxpupuli/modulesync_config,voxpupuli/modulesync_config