[super] User related improvements (login, user pages etc)

[rgrp]

• Minor: sidebar of register page should point to login page rather than openid signin
• Improvements to registration
  • Require email field
  • Require email confirmation to be activated (?)
• #1311 - modal user login
• Do not allow account creation via OpenID (only login)
  • need to allow association of openid to an account (how do we do this?) -- simply paste of url is possible but won't work for google with their weird openid urls
• User page UX:
  • show member since
  • Allow users to provide a home page, organization
  • Display email?
  • Should have activity (once activity available)
  • List all owned datasets (in standard manner)