Add separate check scheme

The address sanitizer prints spurious warnings; create a separate
"check" scheme that enables the sanitizers and use "displaymode" for
releases.

Bump to version 1.3.3

No logic changes; but this version will be built for Apple Silicon as
well as Intel.

Bump version to 1.3.2

Also bumps copyright notice to 2021.

Fix crash when display is not specified

xcode scheme changes

Run with "d" by default.  Xcode has also moved some tags around.

Copyright & version bump to 1.2.0

Version bump: 1.0.1

Use semantic versioning