v0.3.2
Some commands, such as `DS`, `BANK[n]`, etc, don't allow the use of negative constants, but there wasn't any check to prohibit the code from trying to do so. This patch adds the `uconst` type to the parser to use when a constant is expected, but it mustn't be negative. Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>