* Add a tab bar to the top of the Palette window that has two
radiobuttons for "Palette" and "Doodads"
* UI: add the concept of a Hidden() widget and the corresponding Hide()
and Show() methods. Hidden widgets are skipped over when evaluating
Frame packing, rendering, and event supervision.
* The Palette Window in editor mode now displays one of two tabs:
* Palette: the old color swatch palette now lives here.
* Doodads: the new Doodad palette.
* The Doodad Palette shows a grid of buttons (2 per row) showing the
available Doodad drawings in the user's config folder.
* The Doodad buttons act as radiobuttons for now and have no other
effect. TODO will be making them react to drag-drop events.
* UI: added a `Children()` method as the inverse of `Parent()` for
container widgets (like Frame, Window and Button) to expose their
children. The BaseWidget just returns an empty []Widget.
* Console: added a `repl` command that keeps the dev console open and
prefixes every command with `$` filled out -- for rapid JavaScript
console evaluation.
* Increase the default window size from 800x600 to 1024x768.
* Move the drawing canvas in EditorMode to inside the EditorUI where it can
be better managed with the other widgets it shares the screen with.
* Slightly fix Frame packing bug (with East orientation) that was causing
right-aligned statusbar items to be partially cropped off-screen. Moved a
couple statusbar labels in EditorMode to the right.
* Add `Parent()` and `Adopt()` methods to widgets for when they're managed
by containers like the Frame.
* Add utility functions to UI toolkit for computing a widget's Absolute
Position and Absolute Rect, by crawling all parent widgets and summing
them up.
* Add `lib/debugging` package with useful stack tracing utilities.
* Add `make guitest` to launch the program into the GUI Test.
The command line flag is: `doodle -guitest`
* Console: add a `close` command which returns to the MainScene.
* Initialize the font cache directory (~/.cache/doodle/fonts) but don't
extract the fonts there yet.
* Create a configuration directory to store the user's local levels
and doodads. On Linux this is at ~/.config/doodle
* Unify the file loading and saving functions: you can type into the
console "edit example" and it will open `example.level` from your
levels folder or else `example.doodad` from the doodads folder, in the
appropriate mode.
* You can further specify the file extension: `edit example.doodad` and
it will load it from the doodads folder only.
* Any slash characters in a file name are taken literally as a relative
or absolute path.
* The UI Save/Load buttons now share the same code path as the console
commands, so the `save` command always saves as a Doodad when the
EditorScene is in Doodad Mode.
