* Overhaul the clunky old alpha Edit Level/Doodad menu with a modernized
version featuring the new ListBox widget.
* The new level loader is a Window that can be spawned from anywhere instead
of on a dedicated MenuScene.
Updates to doodad scripts:
* Actor.IsOnScreen() checks whether an actor's visual sprite box is on-screen
in the level viewport. `Self.IsOnScreen()` will check for the current actor.
Other changes
* PlaySound() to deduplicate the same sound effect from playing at once.
* SDL2 builds of the game now set their app window icon.
* Create/Edit Level window is updated to show a tabbed UI to create a
new Level or a new Doodad. The dedicated main menu button to create a
new doodad (which immediately prompted for its size) is replaced by
this new tab's UI.
* Edit Drawing/Play Level window is more responsive to smaller screen
sizes by drawing fewer columns of filenames.
* Bugfix: the Alert and Confirm modals always re-center themselves on
screen, especially to adapt between Portrait or Landscape mode on a
mobile device.
* The Publisher is all hooked up. No native Save File dialogs yet, so
uses the dev shell Prompt() to ask for output filename.
* Custom-only or builtin doodads too can be stored in the level's file
data, at "assets/doodads/*.doodad"
* When loading the embedded level in the Editor: it gets its custom
doodads out of its file, and you can drag and drop them elsehwere,
link them, Play Mode can use them, etc. but they won't appear in the
Doodad Dropper if they are not installed in your local doodads
directory.
* Fleshed out serialization API for the Doodad files:
- LoadFromEmbeddable() looks to load a doodad from embeddable file
data in addition to the usual places.
- Serialize() returns the doodad in bytes, for easy access to embed
into level data.
- Deserialize() to parse and return from bytes.
* When loading a level that references doodads not found in its embedded
data or the filesystem: an Alert modal appears listing the missing
doodads. The rest of the level loads fine, but the actors referenced
by these doodads don't load.
* File->Publish Level in the Level Editor opens the Publish window,
where you can embed custom doodads into your level and export a
portable .level file you can share with others.
* Currently does not actually export a level file yet.
* The dialog lists all unique doodad names in use in your level, and
designates which are built-ins and which are custom (paginated).
* A checkbox would let the user embed built-in doodads into their level,
as well, locking it in to those versions and not using updated
versions from future game releases.
UI Improvements:
* Added styling for a "Primary" UI button, rendered in deep blue.
* Pop-up modals (Alert, Confirm) color their Ok button as Primary.
* The Enter key pressed during an Alert or Confirm modal will invoke its
default button and close the modal, corresponding to its Primary
button.
* The developer console is now opened with the tilde/grave key ` instead
of the Enter key, so that the Enter key is free to click through
modals.
* In the "Open/Edit Drawing" window, a "Browse..." button is added to
the level and doodad sections, spawning a native File Open dialog to
pick a .level or .doodad outside the config root.
* The "Use Key" (Q or Spacebar) now activates the Warp Door instead of a
collision event doing so.
* Warp Doors are now functional: the player opens a door, disappears,
the door closes; player is teleported to the linked door which opens,
appears the player and closes.
* If the player exits thru a Blue or Orange door which is disabled
(dotted outline), the door still opens and drops the player off but
returns to a Disabled state, acting as a one-way door.
* Clean up several debug log lines from Doodle and doodad scripts.
* Take advantage of the new Window Manager feature of the UI toolkit.
* Move the MenuScene's "New Level" and "Play/Edit Level" windows into
stand-alone functions in new pkg/windows/ package. The 'windows'
package is isolated from the rest of Doodle and communicates using
config variables and callback functions to avoid circular dependency.
* MenuScene calls the window constructors from the new package.
* Add an "Options" button to the Menu Bar in the Editor Scene, which
opens the "New Level" window to allow changing the wallpaper or
bounding type of the level currently being edited.
* Move the cheat codes into their own file, cheats.go
