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
In Segment.Split, we didn't take cell width into account
when calculating the offset, which resulted in some "fun" bugs.
I've added a new overload for Segment.Split and obsoleted the old one.
Closes#150
Removed the verbs from all extension methods that manipulate
properties which makes the API more succinct and easier to read.
Also added implicit conversion from string to Style.
As a good OSS citizen, I've obsoleted the old methods with
a warning for now, so this shouldn't break anyone using
the old methods.
