SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
Actions are now shared between menu bar and toolbar. Adds an edit
menu to complement toolbar actions. Glyphs are now passed as ints
instead of u8s; fixes Latin Extended+ glyphs failing to update in
real time on map. Converts weight and type to more human-readable
combo box lists. Selected glyph now scrolls into view on load.
This makes it easier to work in FontEditor at low resolution.
Previously glyph map resized itself and the parent window to
accomodate fonts, which isn't ideal. Users typically control
window size/position after launch; widgets have to make do.
