needed for Kitchen Control

ATTENTION: program development is still in progress!
(S/W compiles, but NOT yet tested)

this is a S/W for one of 3 ProTrinkets, which detect (max. 7) open drawers,
by using an Ultra Sonic transmitter per drawer, which is attached at the far end of the drawer.
All open drawers are signalled to the KitchenControl Arduino (BT Feather), which steers RGB- and WW-LEDs
(see the overview png file in erWINter/KitchenControl)

LCD_I2C_optional.h:
if included, this module provides extra information via I2C to a 16x2 LCD screen
It shows either:

• open percentage via bar-graph level (like VU)
  
• or it shows the text messages sent to Kitchen Control for open drawers
  see following example:
  text = "3m50 5o99 7u05" means:
  
• in cabinet# 3 is the middle(DE:mitte) drawer half (50%) open
  
• in cabinet# 5 is the upper(DE:oben) drawer full (99%) open
  
• in cabinet# 7 is the lower(DE:unten) drawer nearly closed (or 5% open)