* Mailgun notify service
* Update dependency to version 1.3
- The provided credentials (including the domain) are now checked during
startup, as requested by @balloob
- The domain name is now optional
- There's a new config item "sandbox" which indicates whether to use the
sandboxed domain in case the domain is not set
* Fix a few lint issues
* Disable lint check no-value-for-parameter
Fabian Affolter
Philipp Schmitt