Removed UsedCodesManager from CounterAuthenticator
Update README.md
Fix typo
Merge branch 'master' of https://github.com/dusk0r/TwoStepsAuthenticator

Conflicts:
	README.md
	TwoStepsAuthenticator.UnitTests/UsedCodesManagerTests.cs
	TwoStepsAuthenticator/CounterAuthenticator.cs
Readme update - IUsedCodesManager usage