Possible fix for previewing pages with inherited templates.
'engine' -> 'extension'. Update name of Testing Guide. Explain commands to run after generating extension. Explain 'author missing' warning.
Add custom_slug in the allowed params list.
Merge remote-tracking branch 'weedySeaDragon/2544-gemspec-author-note--engineToExtension'
Merge pull request #2388 from Rakoth/master

Possible fix for previewing pages with inherited templates.
Add spec test for checking that the "Add Image" to page button works and that the image on the page still works after updating the image.
Remove httparty from test from 3277e67e8afb039500683f414b2df98e5e176fe9
Set a more liberal Bundler and Rails dependency and update authors.
Update Gemfile to use rubygems for friendly_id
Use Rails 4.1.0.rc2
Rails ~> 4.1.0 and awesome_nested_set from git
Updated asset references to work with Rails 4.1
Fix the preloader API which changed in Rails 4.1
Rendering nothing doesn't trigger the layout in Rails 4.1.