added expiring_pixi_notice.html.erb view
added send_expiring_draft_pixi_notices rspec test
added send_expiring_pixi_notices rspec test
added send_expiring_pixi_notice function to usermailer.rb
added expiring_pixis function to retrieve all pixis that were expiring within a certain number of days
added rspec test for expiring pixi function for Listings
added rspec test for expiring pixi function for TempListings
added send expiring pixi notices and send expiring draft pixi notices tasks to manage_server.rake to send notification emails to expiring pixi users
Merge branch 'develop' of github.com:sdbmich1/plumboard into expiring_pixis