Add mercury to the app
Clean up
Bootstrap and Mercury seem to be in conflict.

- Checking in (even though broken), then reinstalling mercury
Basic implementation of mercury works

* Fixed issue where Z order of editor was preventing toolbar links from being accessible.
Basic controller to handle page updates.
Working prototype of Mercury

* Can update page title
* After updating a page via Mercury, it refreshes
* Refactor error handling to provide stack traces
Add helper for editable_page_title.

* Add a more complex template to test behavior of CSS.
Prototype of editable content blocks

* Html block content can be updated via in context editing

Very hard coded and has some errors.
Removing 'Editor' toggle

* Preview toggles the container and 'add' buttons.
* Add buttons to add content to the container.
*
Clean up styling
Add toolbar buttons for blocks

* up/down/remove from page
Add Move Up/Down toolbar functions for blocks.

* Force reloads the page after moving
* Always works with the first content block, rather than the selected one.
* Users is prompted to 'Leave Page' with popup, which is undesirable.
Move up/down will use currently selected element.
Can remove blocks from In Context pages via toolbar button.
Save page content after moving blocks up/down.

This prevents asking a user about whether they want to reload.
Remove unnecessary editor toggle.
Allow any block to be in context edited.

* Add a 'show' helper, valid for block templates.
* Show will make a field editable by mercury
Refactor to handle mass assignment security.
Use Minitest

* Replace Test::Unit with a newer version of mintiest.
* Primary reason: Nested describe contexts should make test intent clearer.
Add global error handler for page toolbar.