Adding notFoundCallback to thumbs.History

Added a `notFoundCallback` so you can have more control over what to do when a route is not matched.

 - [ ] @andymoon 
 - [ ] @achura 
 - [ ] @doug-martin 
 - [ ] @jgchristopher 
 - [ ] @jkc 
 - [ ] @jvanwinkle 
 - [ ] @ruzz311
 - [ ] @TechnotronicOz