It now no longer requires the modality to be absorbing by default; it
only should be absorbing when non-affine hypotheses have been cleared.

They are split into:
1- KnownMakeXXX , which only works if the parameter is not an evar. Hence, it will never force this evar to becomes e.g., emp or True.
2- MakeXXX, which works even if this is an evar, but it only has instances that will not instanciate arbitrarilly this evar.

As requested by @jtassaro.

- Better error messages
- Handle more inputs

Repair the plainly modality

See merge request FP/iris-coq!122

Thanks to @jtassaro for reporting.

As suggested by @jjourdan, and proved in the ordered RA model by @amintimany.

This should solve the paradox in #149.

General Invariant Tactic

See merge request FP/iris-coq!116

Fix regression in iGPS caused by eebe055b.

See merge request FP/iris-coq!120