Add initial FIGlet docs

Add docs for text prompts

Add net5.0 target framework

Add support for table footers

Fix overflow splitting bug

Closes spectreconsole#93

Don't throw when console is small

this just returns an empty collection when
take is 0. It leads to some strange output, but
it doesn't blow up.

 spectreconsole#93

Add support for rendering exceptions

Update examples

Move console encoder to rendering namespace

Fix bug with uris being interpreted as emojis

Closes spectreconsole#82