Fix some cont issues with shared_ptr.
Bump required Boost version to 1.48.

Bumped because Boost 1.46 has a C++11 bug that was fixed in 1.48. Also simplifies configuration because timer was changes from 1.46 to 1.48.
Add back boost config line in CMake file.
Fix cpp lift-drag demo. Python version still needs fixing.
Merge branch 'garth/test-c++11'
Merge branch 'garth/fix-lift-drago-cpp-demo'