GitLab

- Make use of the fact that https://gitlab.mpi-sws.org/FP/iris-coq/issues/184
  has been fixed.
- Fix indentation.
- Always name hypotheses.
- Make use of `set_solver` to discharge set related stuff.
- Don't import stuff we don't need.

- Add awp_pure to lifting.v
- Prove a_load without unfolding awp
- Use IntoVal in some rules in monad.v