Move button control to its own file and use more Material-like styling
Fix ink ripple not fading out when mouse leaves element

Fade out the ripple if the mouse exits the element
whilst pressed.
Improve alignment and styling of details list

 * Vertically align left edges of item title and item
   fields in details view

 * Vertically align left edge of item title and account
   in item list with item title and fields in details view

 * Follow item list design specs better:
   - 72px to left edge of item title/sub-title
   - 72px item height
   - Use Roboto Draft (aka 'new Roboto') as the app font
   - Use 0.87, 0.54 as alpha factors for primary / secondary
     item text
Improve smoothness of rounding for icon images in item list

Previously the icon images were being clipped twice, once
by border-radius applied to the image itself and again
by border-radius applied to the container.

This resulted in aliasing along the edges of icons which
filled the 48x48px container on non-high DPI displays.

Applying only border-radius to the outer container
for icons which fill the container gives a smooth
anti-aliased outline.
Set the mime type when creating blob URLs for site icons

Previously the blobs were being created with the default
text/plain mimetype.

Using the correct mimetype has no visible effect since
browsers handle incorrect mime types for URLs anyway
but it fixes warnings.
Transfer Roboto fonts over HTTPS

In future we'll want to bundle the font so it works
correctly offline. For now, make sure we're transferring
all resources over HTTPS
Make ripple effect work on non-white backgrounds

Draw the ripple as a translucent black layer over the
underlying background.
Polish section dividers and item titles

Adjust font sizes and spacing for these elements as per
MD design specs.
Add controls to rename and delete sections

In edit mode, replace section title with an edit field.
Deleting this field removes the whole section.
UX improvements for adding new websites

 * Use primary palette color for 'Add Website' action
   and warning color for 'Delete' action

 * Auto-focus newly-added website fields