always set a finalpath
use the builddir name for default finalpath
Merge branch 'skip_source_steop' of github.com:JensTimmerman/easybuild-framework into skip_source_steop

Conflicts:
	easybuild/framework/easyblock.py
add gen_builddir function, call it before self.builddir is ever needed; add unit tests for generating/making build/install dirs
Merge pull request #792 from boegel/skip_source_steop

make sure finalpath is always set for sources, add gen_builddir function