This commit is a major semver bump. Every progra utilizing escape codes generated by Termion is likely broken. The main change is to make each escape has their own type implementing the Display trait.

- Use formatters, mainly Display for escapes.

- Add Truecolor support (`color::Rgb`).

- Put each primitive into distinct modules.

- Add is_tty for checking if some stream is a TTY.

- Add multiple new examples.

Implemented mouse input

Add more controls

The event system has been reworked to allow the detection of mouse
events as well as key presses.
Xterm, rxvt and X10 emulated escape codes are supported, they are
enabled and disabled by sending the right escape codes when creating a
RawTerminal.

To allow for byte manipulation, which was necessary to implement those
features, the backend iterator has been changed from chars() to bytes()
(with specific treatment of unicode sequences), making the whole crate
not require nightly rustc.

added more special keys

Key now supports Home, End, PageUp, PageDown, Delete, Insert and
Function keys. All this is done through the detection of both VT100
escape codes and more modern standard counterparts.
For instance, F2 can be both
    ESC OQ
on VT100, screen, and some versions of xterm and
    ESC [12~
on rxvt and other xterm versions depending on your terminal

Add support for scrolling up and down, and moving the cursor up and
down.

Alternative fix for compilation on Redox

fix cursor moving