preparing for 1.8.7 release

1.8.6 release.

Prepare v1.8.5 release

- MeshHalfedges: function for taking region into account was confusing,

with an implicit conversion to bool. Created another overload to
disambiguate.
- Preparing Release 1.8.4

Fixed warning (param name shadowing)

Change 1.8.2-rc to 1.8.2 (preparing for release)

Restored version number 1.8.1 before creating release assets (oops)

First tagged version