* merge in much of the dav_rework branch: (the drift was becoming to big, no function...

* merge in much of the dav_rework branch: (the drift was becoming to big, no functional changes)
* make configure search for cunit
* rename struct floor to Floor, since floor was already taken by math.h
* move over most of the functions from webserver.c to sysdep.c so main() is isolated and more easy to be replaced by another main in a test-suite-binary
* add first unit test implementations
  - test the LANG header parser
  - start testing the floor evaluation