cmake: Cut some comments.
interfaces: Split out `restrict_initial` from `restrict`.
interp: Flense.
pfasst: Add `tag` helper and state V-cycle on finest level.
cmake: Restore and flesh out comments.
Merge branch 'development' into feature/flense

Conflicts:
	include/pfasst/encap/poly_interp.hpp
Merge pull request #60 from memmett/feature/flense

Tidy and flense various.