- Add more documentation;

- Set the @api visibility tag for documentation.
  - Add further configuration for Yard.
  - Move 'On Defining Events' to 'Vedeu Events' file.
  - Add 'Vedeu API' and 'Vedeu Events' documentation.
- Reorganise project structure;
  - Move classes from `support/` (which was becoming a grab-bag for all
  functionality), into new `input/` and `output/` for input and output
  related classes respectively.
- Refactor case statements into hash tables.
- Change `add` interface on Refresh; introduce `add_interface` and `add_group`
  to remove uncertainty of success from single `add` method.
- Protect against nil with default values; Also, use floats as this reminds us
  that we can have sub-second delay or debounce.
- Add `context` back into Minitest.
- Add placeholder files for unit tests, add and update a few tests and
  continue trying to write integration tests. Also reduce intermittent test
  failure by resetting Vedeu after each test.
- Force use of log even if configured not to, also don't filter certain classes-
  give 'em the lot.
- Refactorings;
  - Remove files no longer required and dead code.
  - Add focus events and re-order alphabetically.
  - Fix parent to return just the view attributes instead of the whole object.
  - Fix Compositor to combine the correct attributes.
  - Fix Presentation parent attribute rendering.
  - Don't register focus events for now.
  - Fix up tests.
  - Prefer single quotes for strings without interpolation.