Split up set2 unit test to reduce compiling time and memory
issue#11: tests/unit: changed .h file guard prefix to CDSUNIT_xxx
Removed unused vars
Unit tests for set are only with C++11 std::set and std::unordered_set
Replace cds::lock::scoped_lock with std::unique_lock, remove cds/lock/scoped_lock.h
Replace cds::ref/boost::ref with std::ref, remove cds::unref and cds/ref.h header
Move libcds 1.6.0 from SVN