Use C++ for compiling the code.

The code doesn't compile right now, but we will get rid of the problems
soon, hopefully.
README.md: Bump date.
README.md: Integrate README.IMPORTANT into README.md

We still have to see which parts are really important and which are not.
Update copyright years.
avr-evtd: Convert some defines into constants.
avr-evtd: Unclutter calls with pass-by-reference.
avr-evtd: Use C++-style memory allocation.
avr-evtd: Limit potential buffer overflow.
avr-evtd: Fix typo.
avr-evtd: Clarify which partition we are dealing with.
avr-evtd: Fix meaning of code with proper parentheses.
avr-evtd: Reduce scope for *some* variables.

There is so much more hard work to be done in refactoring this nasty code.