Remove exmpales/Makefile as obsolete
Add Olimex's AVR-MT128 board
Disable macro poisoning from libavr

Macro poisoning is too powerfull as it also makes error in this case
```c
#pragma GCC poison FOOBAR

#ifdef FOOBAR
  // do something
#endif
```
Fix typecast to have any point
Enhancements for makefile to be interfaced from GUI
Make serial.hh work on boards with only one serial interface.
Fix indentation in autounion.hh
Implement simple hardware I2C support.
Implement an I2C HD44780 LCD interface.

lcd_hd44780: In LCDInterface_I2C, only commit status when absolutely necessary.

lcd_hd44780: Remove debug code.

lcd_hd44780: Add a comment.
lcd_hd44780: Add I2C-based example.
lcd_hd44780: Use a templated backpack struct
lcd_hd44780: Implement LcdBackPack structs using template specialization