add dependency injection

Merge branch 'release/2.0.0' of https://github.com/petrovich/petrovic…

…h-net into release/2.0.0

* 'release/2.0.0' of https://github.com/petrovich/petrovich-net:
  Update NPetrovich.dll.nuspec

Update installation guide

update todo in readme

Merge pull request #4 from quozd/refactor-tests

extract test data factory to separate file