Introduce CppUnit::assertEq(), CPPUNIT_ASSERT_EQ, CPPUNIT_LOG_EQ

In contrast to CppUnit::assertEqual(), does not require for both actual and expected
  values to be of exactly the same type; implicit cast from expected to actual is allowed
Use compiler builtins for swapping bytes in endianness changers, where possible
pcomn_hash header cleanup
Implement pcomn::uuid and pcomn::MAC literal classes