v0.4.0

What's Changed

• Support for function calls and a single builtin function by @froth in #42
• Check for wrong function arity by @froth in #43
• Support for function declarations with closures by @froth in #45
• Add Resolver to fix scope issues by @froth in #46
• Report an error in resolver when trying to return from top-level by @froth in #47

Full Changelog: v0.3.0...v0.4.0