make pack_{str,slice} const fn & bump version to 0.1.1
forgot w is a letter in the alphabet...
basic evaluator
impl From<String> for Lisp
impl From for Lisp for i64, &str, Option
match with string literals and str() patterns
improve match_expr! & add try_match_expr!
impl Display for Lisp
add match_expr! to match&destructure lisp exprs more conveniently
initial commit