Let two struts complete in setup.

- When the code starts it will now let two struts level before continuing.
Level strut1 and strut2 first.

- When system is startad it's supposed to be in a state where all
  suspensions are low. I'm not sure the compressor can fill all four
  struts at the same time. This change make it first level 2 of them.
Update to compile on new Cosa.

- need to cast string to (str_P) to make it compile with newer Cosa's.
Split to .hh-file.

- Split definition to own .hh file.
It compiles!

- Rewritten Compressor as a singleton.
- Added documentation.
- Moved all code for Compressor and Strut to own .hh file.
Added doxygen file.
Added Makefile that uses Cosa build system.
Revert "It compiles!"

This reverts commit 906dc5b4aff20f4338b16c5502f933acb726d839.
Ignore stuff.