[FIX] Yara: used C++11 thread instead of Thread class
Merge pull request #609 from esiragusa/fix/yara/prefetch

[FIX] Yara: fixed random aborts
[FIX] Fixing resource leak in tests system.

Leak was not critical, occurred at the end of a test suite run.
Merge pull request #611 from holtgrewe/fix/test-system-dir-resource-leak

[FIX] Fixing resource leak in tests system.
[FIX] Removing tentative div-by-0 error in alignment_free.
Merge pull request #613 from holtgrewe/fix/alignment-free-div-by-0

[FIX] Removing tentative div-by-0 error in alignment_free.
[FIX] minor fixes