Accidentally had broken the combination of --test and --link-test
Moved unit tests into their own directory.
Added in compilation of docs examples during --link-test. This should prevent docs examples becoming wrong over time.

Removed boost::result_of, restoring std::result_of. This will break GCC 4.7, but I'll fix that up in a moment.

Fixed unit tests not finding test_functions.hpp.

Added unit test for dispatcher->page_size().