Add support for hex, oct, and binary integer literals

Adds support for int literals described in https://go.dev/ref/spec#Integer_literals. This includes hex literals 0x123, oct literals 0o123, binary literals 0b101, and underscores in any integer literlal 123_456_789

Add support for URLs

This release adds support for parsing URLs represented via the standard library type url.URL.

First stable release

go-scalar has been stable for some time now, so I'm releasing the current master as v1.