* Rework the Story Mode UI to display level thumbnails.
* Responsive UI: defaults to wide screen mode and shows 3 levels horizontally
but on narrow/mobile display, shows 2 levels per page in portrait.
* Add "Tiny" screenshot size (224x126) to fit the Story Mode UI.
* Make the pager buttons bigger and more touchable.
* Maximize the game window on startup unless the -w option with a specific
window resolution is provided.
* In WASM build, user levels and doodads are written to localStorage
using their userdir path as keys (".config/levels/test.level")
* LoadFile() and WriteFile() for both Levels and Doodads interact with
the localStorage for WASM build instead of filesystem for desktop.
* userdir.ListLevels() and ListDoodads() for WASM scan the localStorage
keys for file names.
* userdir.ResolvePath() now works for WASM (previously was dummied out),
checks for the file in localStorage.
* Add RGBA color blending support in WASM build.
* Initial texture caching API for Canvas renderer engine. The WASM build
writes the chunk caches as a "data:image/png" base64 URL on the
browser's sessionStorage, for access to copy into the Canvas.
* Separated the ClickEvent from the MouseEvent (motion) in the WASM
event queue system, to allow clicking and dragging.
* Added the EscapeKey handler, which will abruptly terminate the WASM
application, same as it kills the window in the desktop build.
* Optimization fix: I discovered that if the user clicks and holds over
a single pixel when drawing a level, repeated Set() operations were
firing meaning multiple cache invalidations. Not noticeable on PC but
on WebAssembly it crippled the browser. Now if the cursor isn't moving
it doesn't do anything.
Noah