Loading all Keys (facts and violations) after server start

Loading all Keys after server start to avoiding unnecessary queries
Fixtures: Removed commented code
Improving TestBodyFacter

Added test_can_get_fact_definitions
Improving TestCSSFacter

Added test_handle_url_loaded_with_empty_content
Improving TestHeadFacter

Added test_can_get_fact_definitions
Improving TestJSFacter

Added test_handle_url_loaded_with_empty_content
Improving TestLinksFacter

Added test_link_looks_like_image
TestLinksFacter: Fixed class name