2 new rules, removing console spam, minor tweaks, new settings page

New in this version:

• Two new audit rules ("An element's ID must not be present in more that one aria-owns attribute at any time" and "Avoid positive integer values for tabIndex")
• Generalized "aria-labelledby attributes should refer to an element which exists in the DOM" to "ARIA attributes which refer to other elements by ID should refer to elements which exist in the DOM"
• Improved logic for “The purpose of each link should be clear from the link text”
• New-style settings page available in Chrome M40 and higher
• Fixed annoying "axs is not defined" spam in console.