multiple improvements

add lcd_clear_eol(), lcd_chars(), lcd_char(), lcd_fill() functions

add support for four-row displays

add support for programming custom characters
syntax error
WIP UI for lighting controller box
handle long integers
add event_drain() and event_sleep()

event_drain() drains all events from the queue.

event_sleep() enters one of the AVR sleep modes until
an interrupt generates an event.
interrupt control methods and a bit of debouncing

Added encoder_interrupt_enable() and encoder_interrupt_disable()

Added a 50us delay to the interrupt handler to allow input to
settle.
add EV_BUTTON event for button presses
Final (?) code for lighting controller

Added user-interface with multiple editable fields

Added delay code for oneshot and strobe modes

Seems to work...