Added a exception handling for when was specified the invalid value in the pagination parameter.

[example of invalid value]
  * page=-1 (negative numeric)
  * size=a (not numeric)
  * sort= (not specified)
  * sort=,DESC (not specified property of sort target)
  * etc ...

Current implementation of the PageableHandlerMethodArgumentResolver is occurred IllegalArgumentException, and http response status is returned 500(Innternal Server Error) on the default setting of SpringMVC.
I think a best that http response status is returned 400(Bad Request).

Easy a way for resolve this problem is that catch a IllegalArgumentException in PageableHandlerMethodArgumentResolver, and throw a ServletRequestBindingException.
ServletRequestBindingException is handled by the DefaultHandlerExceptionResolver, and http response status is returned 400(Bad Request).

What Do you think?
If you have a same thinking, Please pushed to a master branch.