improve the fib benchmark a little bit
fix bug with floor
Slight improvement to binary search.

This commit replaces two comparison operators with a single call
to compare. It seems to have no impact on "fast" Order instances
(like Int) but will probably help instances that define less-than
and greater-than via a (potentially slow) compare call.
update to ScalaTest 2.0
migrate to typelevel discipline
Fix some bugs uncovered by new ScalaCheck/ScalaTest versions.

The bugs cropped up in ULong, Rational, and FixedPoint. Almost all of
them have to do with correctly handling Long overflow/truncation.
It seems like ScalaCheck is being more thorough here than before which
is why we're just seeing these failures.
Merge remote-tracking branch 'origin/master' into topic/computable-reals

Conflicts:
	core/src/test/scala/spire/math/RationalCheck.scala

Fix merge conflict.