Fixed|Client|UI: Small tweaks to widget animations

The style of an animation should be changed after changing its value,
as if it is changed before, the value setter will misinterpret the
current position of the animation.

Also ensured the log widget slides away in the same time span as the
task bar is hidden.
Default Style|Client: Added an on/off toggle graphic
Refactor|Client|GuiWidget: Anyone can request a geometry update
Fixed|Client|UI|LabelWidget: Incorrect layout

Omit gap between text and image if both are not present.
Client|UI|PopupWidget|PopupMenuWidget: Adding custom widgets to menu
UI|Client|ButtonWidget: Adjusted button down state scaling
UI|Client|ToggleWidget: Added ToggleWidget

A simple on/off toggle based on a button. The on/off graphic from the
style is stored centrally by GuiRootWidget.

Uses a procedural image to draw the state of the toggle.
Client|libdeng2|Script: Separated app-specific stuff out of Config.de

The application-specific "appconfig" module is now responsible for
the default configuration of the application (window, console, etc.).
UI|Client|ToggleWidget|Default Style: Tweaked appearance and animation
UI|Client|VariableToggleWidget: Added widget for toggling script variables

Syncs the value of a script variable (boolean) with the on/off state
of the toggle widget.
UI|Task Bar|Refactor: Use VariableToggleWidget for the FPS counter menu item

There is now a proper widget that makes it easier to implement the
FPS toggling (via Config.window.main.showFps).
UI|Client|Console: Added option for scrolling log to bottom on Enter

Using a VariableToggleWidget in the [>] menu.
UI|Task Bar: Tweaked DE logo
Cleanup|UI|Client|Style: Define rich format font parameters in one place

Rich format parameters for the text styles are now all defined in
Style.
Fixed|UI|Client: Errors in previous commit
Cleanup
qmake|Windows|64-bit: Add 'win64' to CONFIG
Fixed|qmake|Debug|Windows: Typo in config_win32.pri related to rc options
Fixed|libdeng2|64-bit: Various implicit size_t to (u)int truncations made explicit
Merge branch 'ui-framework' of ssh://github.com/skyjake/Doomsday-Engine into ui-framework