[plugin] adjust syntax to match PEP8 + fixed some typos
[plugin] optionally map a specific event onto a specific plugin method: needs to be specified during event registration
[plugin] bump up version (1.8) and updated changelog
[plugin] forgot to remove a mapping for the test cases
Merge pull request #130 from FenixXx/release-1.10

[plugin] optional event mapping over predefined methods