This was just supposed to be a new feature for the generic image tool (dithering support), but while working on that things kind of snowballed 😅
* Added dithering support to the generic image tool and the boot logo changer, when converting images to RGB565 format. This uses a Bayer 8x8 matrix, and the overall "strength" of the dither can be controlled - it defaults to what I feel is a sane value. Dithering can help reduce banding effects due to the low colour depth in RGB565.
* Made "fix" scaling mode more flexible in the generic image tool - now there's checkboxes beside the width and height dimensions - if you un-check one, the other dimension will be calculated automatically to keep the input's aspect ratio intact
* Improved downscaling quality in the generic image tool. While working on the dithering feature, I discovered the previous "gaussian resampling" downscaling method I was using introduced distortion in certain situations. I had a lot of fun playing around with possible replacements (I tried 10 new downscaling functions!), and finally settled on a hybrid function that mixes powers-of-two downscaling (with some custom mipmap style cross-blending) with Hermite interpolation. This new method is reasonably quick, gives clean results with no great distortion, and works well with alpha channels (doesn't introduce any dark fringing)
* Generic image tool now shows the dimensions of the output image
* Added a max width on the main tool page bodies, so that they don't get so wide on full-screen desktop browsers
* Fixed a few edge-case logic bugs here and there (e.g., when upscaling only a single dimensions with the generic image tool, or places where I thought I was copying objects, but was only creating references to them, etc.)
* Switched from using "var" declarations across all tool codebases to "let" or "const" instead
* Switched out the SVG alert icons to just use emoji instead
* Various other nips and tucks (fixed up my arbitrary 80-column comment wrapping on the tools that had previously just been eye-balled, fixed a few comment typos, etc.)
Looks like there's a new official firmware version out, and it's got a critical bug with SNES save states - avoid this one!
Updated the tools I host to support the new firmware, complete with warnings about it. Also updated the main Github document with the first details about the firmware, more will come later when my own download of it has completed.
Updated CFW FAQ with the latest details. Corrected a detail about the relationship between arcade `.zfb` files and the `.zip` files they point to (thanks `.ericgoldstein`!). Added a note to the Firmware section about the official firmware update process wiping the microSD card, and a note to the Save States section about how to back up game saves (thanks for the suggestion @uli42! Closes#10). Added a simple firmware version checking tool, so that folks don't have to use the boot logo changer to check (which always seemed clunky to me). Added a link to `dteyn`'s silent sounds pack. Fixed some small typos.
