v2.0

Changelog:

• Every datalogging session (on/off, button iteraction) creates a new 'csv' file with a index on the end of its name.
• User can stop a session by pressing the first button.
• Session indication on LEDs improved.

v1.0

Changelog:

• No more complete file overwrite on reboot. Just append data to the previously created file.
• EOF index retention on a second file named "index.xdk".
• Battery voltage monitoring.
• No known file size limit.