Add leap_check helper method, #3007 related issue.
Merge remote-tracking branch 'ivan/feature/add-leap-check' into develop
Fix events doc about reqcbk signature. Closes #3261
Merge remote-tracking branch 'drebs/bug/3261-fix-events-doc-about-reqcbk' into develop
Fold in changes
Bump version to 0.2.7
Fix path prefix for OSX
Merge remote-tracking branch 'chiiph/bug/path_prefix' into develop
Check if schema exists before load a config.

Related to #3310.
Merge remote-tracking branch 'ivan/feature/check-if-schema-exists' into develop
Handle schemas and api versions in base class.
Merge remote-tracking branch 'ivan/feature/common-code-to-base-config' into develop
Fix old parameter error.
Merge remote-tracking branch 'ivan/bug/fix-old-parameter-error' into develop
Fold in changes
Bump version to 0.3.0
Make ensure_server async
Merge remote-tracking branch 'chiiph-github/bug/ensure_server_async' into develop
Force protobuf version to >=2.4.1.

* Also, generate events_pb2.py file using 2.4.1.
Add events for SMTP signaling.