Use "match ... with ..." statements in compiler and examples

[Akuli]

The code is slightly longer, but much more readable.

Currently match some_byte: doesn't work, but match some_byte with bytecmp does, where bytecmp is the following function:

# TODO: should not be needed
def bytecmp(a: byte, b: byte) -> int:
    return (a as int) - (b as int)