Extend lisp language

[vinc]

• Add mapcar builtin (aliased to map)
• Add ensure_length_eq and ensure_length_gt macros to rust code to simplify eval
• Add div, mod, and exp math functions (aliased to /, %, and ^)
• Rewrite eq function to work on lists
• Rewrite atom function
• Add load function to load lisp files
• Add /ini/lisp/core.lsp with more primitives
• Rename read-file to read