simplify sectioning and hypotheses in Functorish
cancelL_isequiv should not be an Instance (can't guess f)
track axioms more carefully in ReflectiveSubuniverse
implicit arguments to O_functor
more functoriality of O
use modalities for functoriality in Truncations
reflectors preserve products
WIP Freudenthal
Add an INCOMPLETE note to freudenthal
Merge pull request #485 from mikeshulman/functor

Functoriality and product-preservation of reflective subuniverses
Merge pull request #489 from JasonGross/wip-freudenthal-suspension-theorem

Make freudenthal suspension theorem compile