O Clock Versions Save

• #136
  • Remove toNum.
• #139
  • Add Data instance to Time.
• #140
  • Increase some upper bounds.

• Added toFractional, ceilingUnit and ceilingRat.
• Deprecated toNum in favor of toFrational / floorRat.
• Switched the order of the type variables of floorRat for ease of use and consistency with other functions.
• Removed KnownRat unit constraint from timeMul.
• Relaxed dependencies' upper bounds.

Resurrect o-clock in nightly resolver. Specifically:

• Explicitly support GHC-8.8.
• Bump many upper bounds.
• Make benchmarks not buildable by default.
• Drop support for GHC-8.0 and GHC-8.2.

See README.md