Fixed|Unix: Crash when launching application (UnixInfo)

UnixInfo needed to know the application's /etc path, but the application
had not been fully constructed at the time.
UI|Client: Added "24-bit" color depth to Video Settings
UI|Client: Store game selection subset fold state persistently
libdeng2|RuleRectangle: Added midX/midY output rules
Fixed|UI|Updater|libappfw: Updater Settings dialog position while closing

In the Update Available dialog, the anchor where the Updater Settings
was attached (the Gear button) was deleted, which caused the Settings
dialog to be incorrectly positioned while being closed.
Cleanup
UI|Task Bar: Show the "Connect to Server" item in Ring Zero
Network: Querying a subset of found servers from ServerLink
Default Style: Mini version of progress wheel is also a gear
libappfw|ButtonWidget: Added a method for triggering a button
libappfw|ProgressWidget: Color of the mini style can be changed
libappfw|LineEditWidget: Added a frame for text edit widgets
libappfw: Minor improvements
libdeng2|Action: Added as/is methods for Action classes
libappfw|DialogWidget: Added an action for dialog acceptance

When a dialog is accepted (closed with a non-zero result), they may
now be given an action to trigger when the dialog has closed.
UI|Updater: Allow updater mini progress to rotate
UI|Multiplayer: Improved MPSelectionWidget

The multiplayer game selection widget can now notify an audience
when the selection has been made, and the click-to-join feature can
be disabled. This allows the widget to function as a part of another
dialog.

Also, the discovery mode for the widget can be configured.
UI|Multiplayer: Improved manual connection dialog

The manual "Connect to Server" dialog is now substantially more
sophisticated. Once an address has been entered, it starts a query
using ServerLink and shows the results in an MPSelectionWidget.
The game can then be joined by pressing Enter, clicking the dialog's
Connect button, or clicking the MPSelectionWidget's join button.

The dialog takes advantage of an acceptance action to execute the
join. This also works around the issue of not being able to change
games when joining with the "connect" console command.