Don't use the runtime app context for tests
collapse validate-common.sh into validate.sh
test _user_loader
Merge djmitche/build-relengapi:simplify-validate (PR #114)
Merge djmitche/build-relengapi:no-runtime-app-in-tests (PR #109)
borrowed code from https://github.com/buildbot/buildbot/blob/master/common/fiximports.py to fix import issues in #112
added fiximports.py
Merge amyrrich/build-relengapi:fiximports (PR #116)
move `relengapi.proxy` to `relengapi.lib.proxy`
move `relengapi.subcommands` to `relengapi.lib.subcommands`
move `relengapi.db` to `relengapi.lib.db`