Closes gh-16428

Closes gh-16422

Closes gh-16028

Closes gh-16356

Closes gh-16349

Closes gh-16424

Closes gh-16348

Closes gh-16352

See gh-16421

Closes gh-16421

See gh-16418

See gh-16418

Closes gh-16353

Closes gh-16418

Remove a few items that are no longer necessary.

Update the eclipse setup files and contributing instructions for
compatibility with the latest Eclipse 2019-03 release. This commit
reverts the use the HTTPS in the `.setup` file namespace (since it
breaks the setup editor). The `xsi:schemaLocation` section still
uses HTTPS for actual XSD resolution.

See gh-16245

Closes gh-16068

Closes gh-16346

Closes gh-16345

Closes gh-16359

Closes gh-16358

See gh-16400

Closes gh-16400

Closes gh-16339