First attempt to move unit test into libs/afio/test

I'm not sure if CATCH has been moved properly or not

The next commit will work on compilation issues, and resolving any issues with submodule CATCH
Fixed include paths for the unit tests

unit tests now compile and run from libs/afio/test

TODO:
1. move documentation to libs/afio/doc
2. complete transistion from NiallsCPP11Utilities to a minimal details folder
3. Replace CATCH with BOOST_TEST
4. move from scons to Boost.Build