release: Bump version 5.1.0 to 5.2.0

Added tag v5.1.0 for changeset 6139e442fab9

merge: Resolved conflicts

ini: cleanup

feat(s3 region): added configurable s3 region.

fix: clone-url test for mercurial uses a consistent and strict non-interactive mode so we never will see password prompts

fix: fixed a bug in test clone url that used a non-credentials based url causing a password prompt

fix(svn): svn events fixes

feat: config change to enable httppostarguments for hg repo, resolves issue with push/pull on big hg repos

archive-cache: synced with CE codebase