This combines the SET and INST instructions into one SET instruction and adds DEBUG for opcode 10.
This is a breaking change, but the migration is very simple.
* Included utility buffer in sketch and reworked it.
* Included the new buffer and instruction changes in the README.
* Implemented the new buffer in the emulator
* Made the buffer clear since no expansion is active
* Added the new buffer and expansion card to the specification document
* Used more consistent wording and added expandability to the goals. Added more examples for expansions.
* Implemented additional input codes in the emulator
* Explained new inputs in the README
* Added additional inputs to the specification and changed the layout.
* Made a more advanced input-tester example that shows all keys.
