Add more commands.

[timlg07]

Adding a bit more advanced commands to make it more similar to a real-world instruction set, enabling you to do things like iterating an array, maybe even doing function calls, etc.

As a reference, the MIPS instruction set could be used and simplified/abstracted.

These commands should be optional and hidden by default. This way this tool stays relevant for usage in the context of the assembler level you learn at school