Prepare next prerelease version.
Added badge to README indicating outstanding issues on waffle.io.
Added URLStringProbe support via `--url-probe` flag.
Updated documentation for `URLStringProbe` and `--url-probe`.
Merge branch 'feature/URLStringProbe' into develop
v0.3.0
Merge branch 'release/0.3.0'
Merge tag 'v0.3.0' into develop

v0.3.0
Fix Travis CI build issues.
Updated VoD rules in `--[un]trusted-ssids` to also use `InterfaceTypeMatch`.
Improve code readability.
Added support for configuration persistance.

- ENV vars.
- `.ovpnmcgen.rb.yml` in `./` or `~/`.
- `--config` option for filename.

Note: All config flags with a hyphen should appear with an underscore
instead. `s/-/_/g`
Added more documentation for configuration.
Updated ChangeLog.
Merge branch 'feature/config' into develop
v0.4.0.
Merge branch 'release/v0.4.0'