new feature: show current and total number of open buffers in title bar

When multiple buffers are open, replace nano's name and version number
with an indication how many buffers are open preceded by the sequence
number of the current buffer.

Signed-off-by: Marco Diego Aurélio Mesquita <marcodiegomesquita@gmail.com>
Signed-off-by: Benno Schulenberg <bensberg@telfort.nl>
5 files changed