Data.Micro: deprecate toMicro

∙ Because it wasn't being INLINEd away like I had imagined.
Data.Thyme.Calendar.Internal.isLeapYear: avoid code duplication

∙ Prior to this commit, INLINE caused GHC to duplicate the core for each of
  the eight alternatives, for everything that follows the call site.
∙ We still want to avoid re-boxing the years argument, hence isLeapYear#.
Data.Thyme.Clock.POSIX.getPOSIXTime: remove dependency on "time"
Data.Thyme.LocalTime.TimeZone: stop borrowing time's TimeZone
Data.Thyme.LocalTime: merge .Internal and .TimeZone

∙ These only existed because I was borrowing time's TimeZone.
Data.Thyme.LocalTime: type {Hours,Minutes} = Int
Data.Thyme.LocalTime: instance {Bounded,Random,Arbitrary} {TimeZone,LocalTime,ZonedTime}

∙ Some slightly dubious implementations of 'randomR'.
∙ Closes #11.
implement Arbitrary (shrink) for ALL THE THINGS

∙ I'm not convinced that these all make sense.
∙ Please file a bug report if you think of something better.
∙ Bonus for #11.
instance CoArbitrary for ALL THE THINGS

∙ Bonus for #11.
Data.Thyme.Internal.Micro: fix rounding issue with (*^); closes #14
thyme.cabal: version: 0.3.2.0