add support for tweaking software version and toolkit from EasyBuild command line, i.e. override whatever is specified in the easyconfig file(s) provided;
along the way, also clean up unused imports, shorten lines that are too long, fix a bug in WRF (self.wrfsubdir being empty in make_module_req_guess), and add extra functions in EasyConfig class required to support the tweaking feature

Conflicts:
	easybuild/framework/easyconfig.py
	easybuild/test/easyconfig.py

Proper way to set the logdir

Categorize easyconfig parameters

Conflicts:
	easybuild/easyblocks/c/cp2k.py

Fix missing import for get_software_root in application.py

Change test-files as well

Conflicts:
	easybuild/framework/easyconfig.py

rename EasyBlock to EasyConfig

Fix tempdir.