Enable advanced color modes in screen/put-string

[charlot-shaw]

Reasoning

I'm poking around roguelike design in clojure, using clojure-lanterna. I wanted to specify the RGB colors drawn, and use more advanced features in the underlying library.

Features

• No API changes for people consuming the library correctly.
• Indexed mode accessible.
• RGB mode accessible.
• Mostly delegates to the wrapped library, so maintenance should be minimal.

Implementation

I have a few questions relating to implementation I'd like to see before this is merged.

1. Is the Markdown in the docstring acceptable? I personally feel it helps with readability, but I'm not a maintainer here.
2. Given put-string is likely to be called a lot, I'm considering adding a core.cache to it, so that we aren't parsing the same string over and over in a hot loop. (This was partially why I setup the TextColor passthrough, to allow users to optimize.) I have no benchmarks, but it is a concern. I also considered a protocol, to allow for faster dispatch, but that felt heavyhanded for a first go.
3. Most of the library doesn't seem to get in the way of any underlying java errors, but providing a bad string now gives a two layered exception, first an IllegalArgumentException, then an error from trying to type-hint the first exception. Between that and the exception making the default return of TextColor$ANSI/DEFAULT no longer guaranteed, it makes me wonder if I should catch and suppress the error.