Show/hide annotations in sidebar.

Includes:
* Showing and hiding using jquery after backbone render.
* This is untested. Feature specs using capybara are not playing well.
* Sorts the annotations by position in the document.
Implement multitenancy via the Apartment gem

Includes:

* Database cleaner config to work correctly with apartment schemas
* Auto-create schemas when a tenant is created
* AdminUsers, Tenant and DelayJob models are "global" across all tenants
* Customize devise mailers to use urls pulled off Tenant#domain
* Interpolate the tenant name into the generated paperclip upload paths
* Add ActiveAdmin tenant config
* Implement a generic elevator that will default to 'public' when no tenant is found
WIP static pages, terms and conditions, devise before_filter refactor.
Revert high_voltage
Make active_admin and authentication play nicely together