Remove copyright headers, update LICENCE file.

Closes #54

See merge request iris/stdpp!124

This follows iris/iris!387
This closes issue #54.

Change mode of `TCEq`.

See merge request iris/stdpp!123

Set `Hint Mode` for logical `TCX` type classes

Closes #55

See merge request iris/stdpp!121

Avoid using Hint Resolve with a term

See merge request !122

This feature is now deprecated in Coq master (see
https://github.com/coq/coq/pull/7791).

Instead of passing a partially-applied lemma directly to Hint Resolve,
first create a definition and then make that reference a hint.

Rename `fin_of_nat` → `nat_to_fin` to follow the conventions.

See merge request iris/stdpp!120

Add destruct_or tactics to (possibly repeatedly) split disjunctions in an assumption

See merge request iris/stdpp!117

The opposite was true before to this commit.

Countable instance for vec, and rename `vec_to_list_of_list` into `vec_to_list_to_vec`

See merge request iris/stdpp!115

Add `set_solver` support for `dom`

Closes #53

See merge request iris/stdpp!116

Rename `cogpick` to `coGpick` (oops).

See merge request iris/stdpp!113

cogset

See merge request !108