Add the means to stylize a row of data.
Provide a way to render that from the Compositor.
Yard: Update method documentation, also;

- Update tests.
Remove inline tests, let's use Cucumber eh?
Little bit of cleanup here and there;

- Add tests for return types.
- Add .reset to Colour class.
- Move escape characters to separate class (Esc).
- Fix @param to use actual variable used.
- Fix @return types.
- Remove 'returns an instance of...' messages.
- Whitespace of course.
Add .size convenience method;

This is now used as the default in the Buffer class.
Add simple value class, also;

- require_relative supporting libraries.
Buffer shall accept Strings and Arrays;

- Remove #content method (not the job of Buffer).
- Remove #invalid_cell checking method.
Add Mask class for Colour pairs.
Remove skipped test.
Add test for version, y'know for completeness.
Add simple Renderer class.
Handle Buffers in Compositor.
Add 'bold' and 'underline' escape codes;

Also, reorder methods.
Yard: Update method documentation.
Rename 'pair' to 'mask'.
Rename 'interpolate' to 'compose'.
Rename 'buffer' to 'composition'.
Add to_s convenience method to view the buffer's contents.
Merge pull request #4 from gavinlaking/escapism

Escapism