Introduce a fake schleuder api daemon for testing

• Replace manual stubbs in all default cases - some manual stubbs for some edge cases are left to not overload the fake schleuder api daemon.
• Adjusted the fixture files for more data consistency in the tests.
• Add launchy gem. When using save_and_open_page in a feature spec it will launch an unstyled instance of the specific page in your default browser.
• Remove .ruby-version file and add it to the gitignore.