pearson_make_tc_user: add support for incremental changes, and changes to 'internal' fields for debugging.

pearson registration - changed accepted classes, content, and styling to use the term process instead

pearson registration - revised UI states for reg form, simplified markup for form fields, synched button styles/text b/t registration form and dashboard

switch back to returning json to test_center_register template, and enable jquery handling in template.

fix migrations, removing one field and making another nullable.  Update registration page to allow for editing only demographics.

Our code breaks on requests >= 1.0, so locking in a version for dev

Revised Georgetown University seal/logo for edx.org use