[README] added tutorial how to get oauth2_token hash
[FIX] unit tests by omitting OAuth2 authorization
[HOTFIX] integration tests by adding monkeypatch helper (no big deal though)
Removed obsolete unit tests
Removed obsolete example: customize_configuration
Updated example: log_to_specific_account
Updated example description: add_invalid_keywords, add_invalid_text_ad
[FIX] example update_text_ad (changed obsolete status)
Version bump 0.2.0