Updates jeditable to use blank defaults for WYSIWYG
Bugfixes, tweaks to in-place editing

The controller change fixes a double-render error which I think was the cause of both [#59878460] and [#58756184] (duplicates, I think).

https://www.pivotaltracker.com/story/show/58756184
https://www.pivotaltracker.com/story/show/59878460
Prevent accidentally zeroing last_src in image_questions

[#60268936] Retaking a snapshot copies `current_src` into `last_src` twice due to different method calls. After the first time, `current_src` is set to ''. This meant the second time, last_src became ''. That prevented the snapshot retake from being properly canceled. This change checks to see if `current_src` is an empty string before allowing it to be copied into `last_src`.

https://www.pivotaltracker.com/story/show/60268936
Cleanup on aisle javascript
Moving duplicate controller code to application_controller.rb
Reorganizing actions in Activities controller

For readability, this groups runtime actions and authoring/admin actions.
Reducing complexity in Activities controller
Refactoring to follow changes in 7e73893311

Found another incidence of the pattern I refactored in that commit, the "respond with nothing" block.
Fixing dirty-run submission refactoring

For some reason calling the submission on the run directly wasn't working. This does.
Simplifying update actions to reduce repetition
Handling MultipleChoiceAnswers with no choices

We were seeing errors for updates with ids of nil (actually id= ) which I believe represented a user reset of the question - maybe a multi-select with nothing selected, for example. Assuming that's valid input, this handles it properly rather than returning an error.
Cleanup, notes on logged errors
Notes on errors
Simplifying the ImageQuestionAnswersController a bit
Cleaning up pending tests to ActivityController
Rspec tests to catch the bug fixed in f2044f8a16
Decomplexifying InteractivePagesController
Remove the run key from the Activity show URL

…and stash it in a comment in the HTML, just in case. [#59858978]

https://www.pivotaltracker.com/story/show/59858978
Keep this route to avoid errors

https://www.pivotaltracker.com/story/show/59858978
Force removal of session key from activity URL