reuse cleanup from Application in IntelBase, clean home dir first, then remove build dir (refs #272)

+ append new buildstats to previous ones.

added a get_cpu_vendor to systemtools, so we are a littlebit more platform independent (should work on osx and bsd now) (closes #259)

revert part of previous commit that put all imports on the top, because it creates a cyclic dependency between build_log and config (config imports from build_log, build_log imports from config)

move all imports to the top, because it seems sometimes an import may fail if it's put 'inline' (see ageorges testing EasyBuild v0.5 on Ubuntu)