Snapshot 23w10d

• asm32: Add tests for out

• Make disk I/O work in alters other than 0

• Reformat the code in the initial blocks

• asm32: assembler with more typical syntax and 16/32-bit as target

• alters: a way around the 64K limit

• Include filesystem contents in repo and disk images

This includes a more full-featured version of the file editor in
fed.fth, a fsck in fsck.fth, a unit test library in test.fth, a file
copying utility in fsext.fth, and a minimal x86 encoding reference in
x86.txt.

• Move intermediate files to build/

• Clean up repo organization

• Save 5 bytes