Qt backend and OSX compilation fix

SmartPtr.hh change cause use of undeclared template in other templates, which fails in Clang, tr1::unordered_map also not available on Clang/OSX, so reverted SmartPtr.hh to master version.

Qt backend is cleaned.

added math_view namespace to fixed, I remember you said namespace should be added to all units, but fixed is only used internally by scaled and no backend or frontend code use it, if namespace only represent an internal meaning it's fine because there's no name conflicts in other units. If add namespace to all other units the code may be verbose.