Also, make our redefinition of done more robust under different
orders of Importing modules.

Since Coq 8.4 did not backtrack on eauto premises, we used to ensure
that hints like

  Hint Extern 0 (?x ≡{_}≡ ?y) => reflexivity.

were not used for goals involving evars by writing ?x ≡{_}≡ ?y instead
of _ ≡{_}≡ _.

This seems to be a legacy issue that no longer applies to Coq 8.5, so
I have removed these restrictions making these hints thus more powerful.

change statement of inv-open lemmas such that they do not force the invariant, and the 'inner step', to appear right next to each other

Also do some minor clean up.

globalC -> globalF
New notation: iPropG, iFunctorG

It is now slightly below implication. In order to do this, I had to change
the notation from P ={E1,E2}=> Q to P >{E1,E2}=> Q because the prefer ={n
is already used at level 70 for the distance of the metric.

Actual proofs will end up using own and inv, and none of the notions defined in ownership.v

This way we can more easily state lemmas for concrete languages for
arbitrary global functors.