add timestamp helpers to test_functions
use timestamp helpers in 573
FIX: date parsing error message
check error message in test 573
add cp_bin() to test_functions
use cp_bin()
use timestamp helpers in 574
use timestamp helpers in 578
FIX: AUFS warning when machine readable
FIX: detect blanks with grep < 2.6
FIX: harmonise file permissions for test files
FIX: SL5 mktemp compatibility
Merge pull request #632 from reneme/fix-tests

Fix: Garbage Collection Integration Tests on SL5 and SL6