Examples overhaul, hook default props fix, always clear onload event listener

[MatthewHerbst]

• Overhauled our local examples so that every use case is covered. This will improve testing and hopefully serve as additional documentation
• Styles not included in print #11 (comment) Fixed an issue where the useReactToPrint hook was not properly setting defaultProps
• Clear onload in all browsers (not just IE)? #254 Ensure the onload event listener is cleared after being called
• Added a FAQ answer about how we don't control settings in the print dialog