* Added `BoxSize()` to Widget that reports the full box size including
borders and margin.
* The Frame uses the `BoxSize()` of widgets to position them.
Reintroduces some padding issues (boxes on the GUI Test stick out of
bounds a bit) but is on the right track.
* Renamed `Padding` to `Margin` on the Widget object, since the Margin
is taken into consideration along with Outline and Border in computing
the widget's BoxSize.
* Restructured the Label widget to take a Text or TextVariable property
and the font settings (render.Text) are in a new `Font` property.
* Frame.Pack() now supports Fill and Expand and works like Tk.
* The GUITest Scene now draws a large window with two fixed side panels,
an expanding body panel, and a fixed footer with buttons. The panels
are filled with other buttons and widgets showing off the Frame
packing.
These properties will be globally useful to all sorts of Widgets and
have been moved from the Button up into the Common widget, and its
interface extended to configure these:
* Padding int32
* Background color
* Foreground color
* Border size, color and style (default solid; raised; sunken)
* Outline size and color
The button adjusts its border style from "raised" to "sunken" for
MouseDown events and its Background color for MouseOver events. Other
widgets such as Labels and Frames will be able to have borders, paddings
and outlines too, but they will be off by default.
The Buttons can now be managed by a ui.Supervisor and be notified when
the mouse enters or leaves their bounding box and handle click events.
Current event handlers supported:
* MouseOver
* MouseOut
* MouseDown
* MouseUp
* Click
Each of those events are only fired when the state of the event has
changed, i.e. the first time the mouse enters the widget MouseOver is
called and then when the mouse leaves later, MouseOut is called.
A completed click event (mouse was released while pressed and hovering
the button) triggers both MouseOut and Click, so the button can pop
itself out and also run the click handler.
* The shell now supports an "eval" command, or "$" for short.
* Runs it in an Otto JavaScript VM.
* Some global variables are available, like `d` is the Doodle object
itself, `log`, `RGBA()` and `Point()`
* The shell supports paging through input history using the arrow keys.
* Added an initial Main Scene
With Labels and Buttons so far.
* Labels are pretty much complete, they wrap a render.Text and have a
Compute() method that returns their Width and Height when rendered
onto an SDL Surface.
* Buttons wrap a Label widget and Compute() its size and takes that into
consideration when rendering itself. Buttons render themselves from
scratch in a "Windows 95" themed way, with configurable colors, border
widths and outline.
