Refs #3089, tweaks and fixes to visitor profile interface and make sure adjacent visitor retrieval works w/ segments.
Refs #3089, #4116, display visitor profile popup when visit in realtime map is clicked.

Notes:
  - Includes new UIControl base type.
  - Fixes cleanup bugs in realtime map and popover closing.
  - Refactored realtime map so as little JavaScript as possible is included in HTML fragments.
  - Allow more than one realtime map to exist on a single page.