Replace AnyNumber with AnyInteger.
- Remove AnyHoldersImpl.h private header.
Add NumberTraits specilization for floating types.
- Add MAX/MIN_EXACT_INT/UINT constants.
Add NumericTraits::CanExactConvert().
Add convert AnyInteger to floating value, if not out of range.
Add AnyEvent (not complete yet).
AnyEvent uses Any instead of boost::any.