CHANGELOG for v1.2.0

Fix typo in CHANGES.md

v1.1.0 release

1.0.0 release

Merge branch 'vcpkg-build'

Manage dependencies using vcpkg. This includes cesium-native. Remove
use of cmake's FetchContent.

Although it has nothing to do with vcpkg, the worldviewer program's
command line argument handling was majorly revised. The --world-file
argument is no longer necessary. A command line arguments can be a vsgCs
world file, a URL to a 3D Tiles tileset.json, or a glTF model.

Merge branch 'v0.4-branch'

Bump version number

Edits to README.md and some changes to examples

Merge remote-tracking branch 'origin/master'