Issue #8: Archive button on menu bar works.

The icon still needs to be swapped out.
Issue #8: Placed archive icon better and gave it an icon.
Issue #8: Got the archive button the action bar of the email.

Still need to fix some visual quirks and a bug where the archive
button won't get placed in the bar if the message gets moved under
the mouse (as opposed to when the mouse moves over the message).
Issue #8: Fixed the mouse over bug on the archive action button.
Issue #8: Fixed visual quirk with icon overlapping in action bar.
Issue #8: Got settings working with the archive button.
Resolved #8: Added an archive screenshot to the welcome screen.