made all functions that must be called from root console static
Made examples work according to the changes
Merge pull request #22 from Pranz/master

Made functions that originally had to be called from the root console object static instead.

This is a breaking change. The `set_fade`, `wait_for_keypress`,
`check_for_keypress` and `flush` methods are now static.

Change code like:

    let mut con = Console::init_root(80, 50, "tcod console", false);
    con.flush();
    let keypress = con.wait_for_keypress(true);

To:

    Console::flush();
    let keypress = Console::wait_for_keypress(true);