Merge pull request #2244 from ctweney/clc-3410-8

CLC-3410 Eighth batch of reorg: lib/canvas
CLC-3410 Move Google proxies to app/models/google
CLC-3410 Put Google proxies into module
CLC-3410 Shorten Google proxy names
CLC-3410 Move some Google and Canvas specs into proper subfolders
CLC-3410 Move various notification-related classes into app/models
CLC-3410 Put notifications classes into Notifications:: module
CLC-3410 Move notification.rb into notifications folder
CLC-3410 Put Notification into Notifications module