Adds a new extension method IAnsiConsole.WriteAnsi that writes
VT/ANSI control codes to the console. If VT/ANSI control codes are
not supported, nothing will be written.
This makes it possible for encoders to output better representation
of the actual objects instead of working with chopped up segments.
* IAnsiConsole.Write now takes an IRenderable instead of segments
* Calculating cell width does no longer require a render context
* Removed RenderContext.LegacyConsole
* Removed RenderContext.Encoding
* Added Capabilities.Unicode
This commit adds support for recording console output
as well as exporting it to either text or HTML. A user can
also provide their own encoder if they wish.
