Bug fixes: Added cuttingedge to list of stages, add canvas-edge to list of app servers

(this could cause problems since canvas-edge is also in list of 'db' servers. May need
to alter deploy.rb to deal with no app servers)
Merge pull request #91 from stevehillman/sfu-develop

Bug fixes: Added cuttingedge to list of stages, add canvas-edge to list ...