Merge pull request #1166 from jmaas/master

Dont reset CONFIG_ARGS as it might have been sourced from sysconfig/defa...
Merge pull request #1167 from jmaas/master

Next release from master will 3.0.0
Merge pull request #1170 from jmaas/master

Ensure all variables are available in PXE generation (#505).
Move all unittests into ./tests/, adjust Makefile accordingly.