Jobs page updates.

Upgrade to Backbone 1.0.0

Set SERVER_EMAIL so that mail_admins works

Disable SSL cert validation for Zendesk API

studio - alerts: synced up styles and sample markup

They are currently using a CA that is not installed on our servers. Since it
isn't a top-tier CA and we aren't submitting anything particularly sensitive
anyway, we don't have to feel too bad about this.

studio - alerts: synced up example HTML to show advanced settings live notification, aria roles, and action classes; integrated typography mixins

Pass through the value (either default or inherited) that a metadata field WILL have if it is not explicitly set.

Hide the Comments Service API key during logging.

Backbone 1.0.0, Underscore 1.4.4

Added unit tests for safe_key() to resolve bug 392.

Vik/fix/oe bugs

kludged in the note tab panel so it can be turned on and off using the policy editor by adding "notes" to "advanced_modules."

Delete two lines.  without this, the xblock fields are never created in cases where the module is "fresh" (ie has no existing data)

Feature/giulio/accessibility