Add forwarding of operator() to reference_wrapper

[philipp.moeller@…]

Adding forwarding of operator() to reference_wrapper will make it comply with the ISO definition of reference_wrapper. The attached patch adds dependencies to Boost.Move and Boost.Preprocessor. The later could be removed by manually expanding the macro. Forwarding in C++03 only works for values, references-to-const and rvalues as this is what Boost.Move provides. In C++11, forwarding works as expected for all kind of values. It might be necessary to make the amount of forwarded arguments configurable, currently it is fixed to 8.

[philipp.moeller@…]

patch to add forwarding of operator() to reference_wrapper