Prove that O preserves products without funext
Delete minus1Trunc.v, close #434
Work around bug 3638

This is https://coq.inria.fr/bugs/show_bug.cgi?id=3638, "Anomaly: Bad
recursive type. Please report." on [set]ting an evar involving
primitive projections
Remove dead code
Exercises 3.4 and 3.5
Better solution to Exc. 3.4
named pose in Exc. 3.4
make "happly" a parsing notation for "ap10"
easy lemma `issurj` for defining surjections
Mike's solution with ap10 path_contr
Add more documentation to tactics in ReflectiveSubuniverse
Merge pull request #512 from marcbezem/master

Exercises 3.4 and 3.5
Merge pull request #516 from mikeshulman/happly

make "happly" a parsing notation for "ap10"
change equiv_tr to tr
isequiv_surj_emb
BuildIsSurjection
extrafancy tactic is unnecessary
Revert other fancy tactic
check for truncatedness of the goal in strip_truncations
Merge pull request #513 from mikeshulman/minus1trunc

Delete minus1Trunc.v, close #434