Number literals

Traditional Forth often uses HEX/DEC switches to go from deci-
mal to hexadecimal parsing. Collapse OS parses literals in a
way that is closer to C.

Straight numbers are decimals, numbers starting with "0x"
are hexadecimals (example "0x12ef"), "0b" prefixes indicate
binary (example "0b1010"), char literals are single characters
surrounded by ' (example 'X'). Char literals can't be used for
whitespaces.