GUI-568: Add escape_braces() method to BaseView class; add base TextEscapedField class to escape double curly braces in the form input value
GUI-568: Replace ng-non-bindable with escape_braces() on instance and volume detail pages.
GUI-568: Leverage Pyramid's BeforeRender event to escape str/unicode variables passed to templates.
GUI-568: Escape braces in form choices for select field drop-downs
GUI-568: Remove ng-non-bindable attribute in places where it's no longer needed
GUI-568: More ng-non-bindable cleanup.  Add comments where we need to keep the ng-non-bindable attribute
GUI-568: Remove ng-non-bindable attr where it's not needed on the login form
GUI-568: Escape double curly braces in error messages displayed in the notifications growl.
GUI-568: Restore ng-non-bindable attribute for variables in tal:repeat statements since we can't auto-escape curly braces there.
GUI-568: Add an optional "escapebraces" param for form choices.
GUI-568: Escape curly braces on key pair, security group, and scaling group detail pages. Also escape curly braces in MarkupSafe objects.
GUI-568: Unescape curly braces in selected key pair and security group on launch instance and launch config wizards to avoid CLC response error
GUI-568: Handle escaping/unescaping of curly braces for scaling group pages
GUI-568: Unescape tags on resource update to prevent escaped tag keys and values from being persisted
GUI-568: Remove debug statement
GUI-568: Convert scaling group name to template variable where applicable to allow auto-escaping of double curly braces
GUI-568: Convert key pair name to template variable where applicable to allow auto-escaping of double curly braces
GUI-568: Fix failing tests
GUI-568: Convert security group name to template variable where applicable to allow auto-escaping of double curly braces
GUI-568: Convert launch config name to template variable where applicable to allow auto-escaping of double curly braces