Add the Stopwork Command and Time Entry Activities

* Add the `stopwork` command, allowing the user to create a new time
  entry for the Issue currently being tracked.
* Add the Activity type to represent Redmine Time Entry Activities.
* Add the getActivities and getActivityFromName functions to retrieve
  Time Entry Activities.
* Add the addTimeEntry function to create a new Time Entry.
* Add the untilValid function to repeat an action until a valid result
  is returned.
* Add the getUntilValidWithInfo function to display a message and prompt
  for input until a valid response is given.
* Add the confirmWithInfo function to confirm a message.
* Add the diffTimeToHours function to convert a DiffTime into a Double.

* Modify the CLI argument types, appending ID or IDENT(VERSION ->
  VERSIONID).

* Fix a bug preventing cause a successful exit when trying to pause when
  time tracking is already paused.
Add Time Tracking Documentation