Add support for octal literals in the compiler.

Additionally, adds three tests: one for the most common case, one that include
the capital O version (0O instead of 0o), and one that checks a bad octal is
rejected.
Merge branch 'master' into octal
Add a feature request future for octal formatted printing.

This looks non-trivial and shouldn't hold up octal abilities, at least in the
use case we desire it for.
Merge branch 'master' into octal
Take Brad's implementation comments into account.
Take Brad's test comment into account.
Merge branch 'master' into octal
Per Brad's suggestion, add entries for octal literals to the section on
literals, following the formatting of hexadecimal and binary digits.
Merge pull request #348 from lydia-duncan/octal

Add octal literals [reviewed by bradc]

This adds support for octal literals in the compiler. Additionally, adds two passing tests: one for the
most common case that include the capital O version (0O instead of 0o), and one that checks
a bad octal is rejected. It also adds a feature request for the ability to print formatted output with
octals within it.

Additionally, this commit adds octal literals to the spec.