Undo color changes to test redox 256 color support

Get terminal size for Redox's kernel terminal

Use env for terminal size in redox

Line-reading logic is now in its own method

To avoid ambiguity.

Mode is somewhat ambiguous term, which is often overused, for that reason I want to avoid it. This is a breaking change, but I don't guarantee stability yet, however I'll do my best to not break things.