For clang turn warnings to 'on' and remove '-pedantic' to avoid Boost PP warnings.
Merge pull request #22 from eldiener/master

For clang turn warnings to 'on' and remove '-pedantic' to avoid Boost PP...
merge from develop.
Merge branch 'develop'
try to avoid issue with < gcc-4.5 - error: 'is_copy_constructible' is not a member of 'std'.
move sync_queue_closed to concurrent directory.
try to get rid of missing std::is_copy_constructible < gcc-4.5.