Merge pull request #659 from ifilippov/master

patch for LLVM 3.3 and test correction at avx2
fail_db.txt update on Linux with new passes
Merge pull request #660 from dbabokin/fail_db

fail_db.txt update on Linux with new passes
Fix task system dignostic to report real reason of the symaphore allocation fail
Fix for existing semaphore problem
Merge pull request #661 from dbabokin/task_diagnostics

Fix task system dignostic to report real reason of the symaphore allocat...
Merge branch 'perf' of https://github.com/ifilippov/ispc
adding target checking in perf.py