SHA of nupic.core updated

to include fix for strerror_r
(but not ->src/ changesm yet)
7d1271c44f0d5ac14be1a4004ba6
Merge pull request #768 from breznak/SHA_update_core

SHA of nupic.core updated
Merge branch 'master' into custom_targets_tests
Revert "Revert "remove run_tests.sh""

This reverts commit 4a7e063d34df2d834db5793b9cb9c9bbf249a66e.
re-reverting, this was not the cause of problem
call run_tests.py --all not make target tests_run_all

because the make has to be executed from build directory
which in this case is not. python $NTA.... --all should work