Began refactoring code for a more consistent style across classes.
Fix a bug that allowed all users to open the UserInfo view.
Highlight UITableView cells when tapped.
Add clear button to the ChatView text field.
Correct notice for topic changes, kicked users.
Clear the user list when disconnected.
Connections are now notified when global settings change.

Fixes a regression introduced in 5880ea0.
Fix a bug where kicked users weren't removed from the user list.
Fix a bug where avatars would lose transparency.
Resize avatar images in the UserInfo view.
Fix a bug where message avatars/nicknames disappeared on disconnect.
Add ability to set a custom, global user icon.

Fixes #12.