Driver: Display: Rework Hd44780 display controller driver.
Add bus abstraction for 4bit and 8bit data bus width.
Add Dual Hd44780 controller class for 40x4 display sizes.
Update Character Display interface to new coding style.
Peripheral: Gpio: Fix AVR implementation of toggle of older devices.
Peripheral: Spi: Adapt AVR to interface and optimize.
Examples: Update avr Hd44780 example.
Quickfix some header text.
Driver: PWM: Fix TLC5940 Spi implementation.