default clock with more purr

please copy the modified menu.py into your root directory, otherwise the screen might not turn on when opening the menu.

buttons:
top right: flashlight
bottom right: screen toggle, automatically turns off after 10s and adjusts to ambient light sensor readings
bottom left: rotates themes. still pretty stock, will make prettier asap.

additional features:
battery indicator on display below 3.8V
blinky red led when below 3.6V