Update Annotor's PDF plugin to 9acc6554 (typed-packaging).

This change was necessary to adapt to updates of the PDF.js version
shipped with newer FF releases.

There were three small changes. Our code now works with both
the old version (currently used with Chrome) and the old version
(embedded in FF).
Use asset spec for blocks template global
Merge pull request #1343 from hypothesis/1333-fix-pdfjs-for-ff

Update Annotor's PDF plugin to 9acc6554 (typed-packaging).
Start building up a pattern library

Starting with the form elements, the new view is available at
/dev/pattern-library and currently only shows form fields.
Move pattern library view to h.testing

This ensures that it's only loaded in development.
Add experimental form styles

These new styles include labels by default and error styles. It also
gives a little more breathing room between form elements.

The buttons now have a more consistent hover/active state without the
glossy highlight and the disabled state looks disabled.
Update the login form to trial new form styles
Use Compass for button gradients
Update registration forms to use new styles
Update the forgot password form to use new styles
Update the activation form to use new styles
Add new btn-clean style

This removes the background and borders from the button.
Update the editor to use the new form styles
Migrated the login form to the new form module

This required adding an additional deform/mapping_item template to
override the labels.
Remove old form classes

From now on the form module should be used and extended.
Fix vertical alignment of form-checkbox inputs
Add crude code preview to the pattern library
Add CSS only loading spinner
Add new loading/success indicators for forms
WIP Form validation on blur