Response readers shouldn’t be constant.
Fix `defspite`.
Fix some bugs.

 - Don’t inherit ielm’s keymap.
 - Create spite-return, use that instead of ielm-return.
 - Don’t eval forms in a temp buffer, it screws up the locals & we
   don’t care for this stuff.
 - Define `spite`, instead of using `defspite`.
Fix some bugs with `spite-make-url`.

 - Support keyword symbols.
 - Use correct arg (w/o querystring args) when building the path.
Add README.
Add TODOs.