Fixed the Boost library search
Fixed the Boost library search

The cmake supplied FindBoost.cmake is broken (at least in cmake 2.8) and
the system libraries are always returned even when BOOST_ROOT is specifically
set and system search paths disabled. This commit provide a work-around for
this problem where the BOOST_ROOT path (if set) is searched for boost libs.

ulrikpedersen/swmr-testapp,ulrikpedersen/swmr-testapp,ulrikpedersen/swmr-testapp