simple library load

prepend ~/.jq to program, for #112 

This is super simple, just to have the basic functionality.

There's obvious flaws with simple prepending: error messages won't know it comes from ~/.jq; syntax errors like an unclosed `"` or `[` or `{` won't be contained within ~/.jq; tree-shaking of builtins won't apply. But it works.

Also, it doesn't work with `-f/--from-file` (that requires a little refactoring and I wanted to disturb the codebase minimally).