working on conversion to coq 8.4 pl2 patched

Now 94% of the way through functors_transformations.v
we needed to make weqtoforallpaths transparent, after all
further changes...
RezkCompletion now works with coq 8.4 patched

The version of Foundations2 used was 9e4e62e7964189217baec0e602f153e9a71ca8a0

The version of coq used was 721167c315dba3d57e83cc4a2bc1cdd7b8bef62e
making it compile under 8.4, thanks to DanGrayson's help
simplify a proof
simplify a proof
abstraction makes a proof clearer

(the subproof is saved in a separate lemma, so we can do "Transparent weqtoforallpaths" sooner.)
simplified a proof, found by DanGrayson
minor change to make it work with coq trunk patched

For some strange reason, the use of "abstract" caused coq
to go into never-never land at the end of the file.
now works with coq trunk patched

coq version:
    	    https://github.com/DanGrayson/coq/commit/f23efe49ae9a806f5a510448897935e9ac56445b

Foundations version:
	    https://github.com/DanGrayson/Foundations2/commit/8908b92887f7704d5f9c946d5930fdec8358a472
merge with upstream changes
set coq-prog-args appropriately for ProofGeneral
Merge branch 'master' of github.com:benediktahrens/rezk_completion into for-coq-8.4

I had to make just one change, to precomp_fully_faithful.v, to get it to run.
PS to commit d7744304f12e08029ea0a0982278297a4bd74d32:

No, the needed change was to functors_transformations.v and
here is the diff:

--- a/functors_transformations.v
+++ b/functors_transformations.v
@@ -423,7 +423,9 @@ Lemma isaprop_full_and_faithful (C D : precategory) (F : functor C D) :
    isaprop (full_and_faithful F).
 Proof.
   apply isofhleveldirprod.
-  repeat (apply impred; intro).
+  apply impred; intro.
+  apply impred; intro.
+  apply impred; intro.
   simpl. repeat (apply impred; intro).
   apply isapropishinh.
   apply isaprop_faithful.
improve TAGS file command
make "functor" apply just for "precategory"

and not for "precategory_data"
Merge branch 'for-coq-8.4' of https://github.com/DanGrayson/rezk_completion