Added

• New DivisibleArithmetic protocol which easily extends average() to Collections of Double, Float and CGFloat.
  Issue: #36 | PR: #38 | Author: David Knothe
• Make most of the API @inlinable for increased real-time performance.
  Issue: #40 | PR: #43 | Author: David Knothe

Changed

• Allow Int.init?(randomBelow:) to use an arbitrary RandomNumberGenerator (instead of just the system one).
  PR: #44 | Author: David Knothe