* Debug mode: no longer enables the DebugOverlay (F3) by default, but
does now insert the current FPS counter into the window title bar.
* ui.Frame: set a default "mostly transparent" BG color so the frame
background doesn't render as white.
* Add the MenuScene which will house the game's main menus.
* The "New Level" menu is first to be added.
* UI lets you pick Page Type and Wallpaper using radio buttons.
* Page Type: Unbounded, Bounded (default), No Negative Space, Bordered
* Fix bugs in uix.Canvas to fully support all these page types.
* Add some encoding/decoding functions for binary msgpack format for
levels and doodads. Currently it writes msgpack files that can be
decoded and printed by Python (mp2json.py) but it can't re-read from
the binary format. For now, levels will continue to write in JSON
format.
* Add filesystem abstraction functions to the balance/ package to search
multiple paths to find Levels and Doodads, to make way for
system-level doodads.
* Build the app with -tags="shareware" to compile the free/shareware
build of the game.
* `make build-free` compiles both binaries to the bin/ folder in
shareware mode.
* The constant balance.FreeVersion is true in the shareware build and
all functionality related to the Doodad Editor UI mode is disabled
in this build mode.
* Add the JavaScript system for Doodads to run their scripts in levels,
and wire initial OnCollide() handler support.
* CLI: Add a `doodad install-script` command to the doodad tool.
* Usage: `doodad install-script <index.js> <filename.doodad>`
* Add dev-assets folder for storing source files for the official
default doodads, sprites, levels, etc. and for now add a JavaScript
for the first test doodad.
Fixes:
* Move the call to CollidesWithGrid() inside the Canvas instead of
outside in the PlayScene.movePlayer() so it can apply to all Actors
in motion.
* PlayScene.movePlayer() in turn just sets the player's Velocity so the
Canvas.Loop() can move the actor itself.
* When keeping the player inside the level boundaries: previously it was
assuming the player Position was relative to the window, and was
checking the WorldIndexAt and getting wrong results.
* Canvas scrolling (loopFollowActor): check that the actor is getting
close to the screen edge using the Viewport into the world, NOT the
screen-relative coordinates of the Canvas bounding boxes.
* Scenes can insert custom key/value labels to the debug overlay and
track string variables in real time
* Added ability to unthrottle FPS in main loop
