Recheck quasiquotes

This makes the elaborator for quasiquotes somewhat more strict, which
prevents unknown names from sneaking in to quasiquotes as well as
causing it to fail if not enough information is provided to solve implicits.
Update tests for rechecking of quasiquotes
Remove unused code
Merge pull request #1382 from david-christiansen/incomplete-quasiquote

Properly type check quasiquotes