Merge branch 'master' into 4.12

Forked the 4.11 release branch, trimmed version number, removed Remot…

…es:, set release check configuration, and updated CITATION.

Merge branch 'master' into 4.10

Merge branch 'master' into 4.9

Trimmed the version number, removed the Remotes: directives, updated …

…CITATION, and switched to prerelease test configuration.

Merge branch 'master' into 4.7

Updated CITATION.

Forked a 4.6 release branch, truncated version number, removed Remote…

…s, updated citation, and set check flags.

Forked a release branch, trimmed version number, updated date, update…

…d CITATION, and set pre-release checks.

Reran revdepcheck with tergm workaround.