Time/Time - documentation updates and minor cleanup

- Removed `Time.pausedTime`

  Time.pausedTime has not been used / updated since
  b255fea85f7b4bb9b0a335a1407300db83e3f671 in Feb 2014.

  There might be a case to re-explore how pause time is
  reported/observable, possibly with a distinction of 'current' and 'last'
  and the semantics of such. For instance, pause duration is only updated
  after the resume occurs and reflects the duration-of-the-last-pause..

- Removed `Time` _i and _len properties These are better suited by local
  variables.

- General documentation updates.

- Marked several methods such as `Timer.order` as protected - there are
  advanced use-cases for them, but different user-facing methods and
  documentations are likely in order. Also marked `Timer.sortHandler` as
  private; but did not change any interfaces.