This expands significantly the maximum number of Beats that can be represented, which is a good
thing in itself. It slightly speeds up some Beats::operator methods, and slightly slows down
::get_beats() and ::get_ticks().
One minor change in an API user was required, and several tweaks to the unit tests due to the
macros being used by cppunit creating possible type confusion.
Units test pass
This just uses the old Evoral BeatTest. Some of the tests needed amending
because temporal uses rint() to convert between float and int, not just
a cast.
