Switch spin function to have defaults.

Allow overriding them with the opts option instead of requiring the caller
to specify the option everytime. Should keep things consistent.
Get import submission interface working.

Fixed a weird bug with the lastImportedDate queries.

Got a basic import submission interface going. Shows success and error
messages to the user obtained from the server. Resets inputs after they
are successfully imported. Leaves invalid inputs untouched. Shows a
progress spinner while waiting on a response from the server.

Also corrected an error where the Sales model was not referenced correctly
on some pages.

Fixed the import link in the nav.

Hid about and contact since they don't have content.

Used JSHint to find problems in import.js, then fixed them.