<1> adding return statement to cereal functions because every evaluation of return type as non-void will require an explicit mention of "return <non-void-type", otherwise will be caught as compile error by our build system.
<2> putting a file for boost_optional support from https://github.com/stevehickman/cereal/blob/master/include/cereal/types/boost_optional.hpp
auto modified file
removing stuff from CMakeLists.txt that had been added to get cereal headers listed in the IDE for modification
Minor fixes to handle updates to OS X version 10.10, CMake Version 3.1 and Boost version 1.57.
Added CMake option to include test targets.
Further updates to exclude tests if required.
Another update in preparation for CMake 3.1.
Merge pull request #165 from ustulation/MAID-413-modify_and_update_cereal

Maid 413 modify and update cereal
Merge pull request #170 from Fraser999/MAID-457

Minor fixes to handle updates to OS X version 10.10, CMake Version 3.1 a...
Merge pull request #171 from Fraser999/MAID-460

Added CMake option to include test targets.