Note on unused opcode 0x3f

Jumps are now all absolute. Finished assembler.

Almost done with all emitters.

Added additional port_write/port_read opcodes so invocation from higher-level languages becomes feasible. Added most assembly emitters.

Added parser.

BIt of parsing.

Removed logging in lexer.

Added nice error messages, binary and hex literals.

Closes #2, closes #3, closes #4

One more typo.

Removed TOC

Updates based on feedback by @binji. Closes #1.

Small corrections.

Added TOC

Initial commit, ISA and overall architecture, basics of lexer.