Clean up the preference pane UI

[dvntucker]

With some of the new UI elements in the preference pane the UI has gotten a little messy and inconsistent. Some of the margins are inconsistent, some of the panes could maybe be collapsed into a single pane, potentially the panes could be separated into separate views for ease of development, etc. I'm also not an IB expert, so I'm sure there may be best practices we are missing there.