Remove  unnecessary use of boost::cref() in framework

boost::cref(this) will no longer compile with boost 1.57.0, and std::cref(this) will not compile either, because these functions do not take an rvalue reference as an argument.
Also, all the use of boost::cref did in this case is *possibly* saving the copying of a pointer, at the overhead of a function call, so it was not a good idea in the first place.
This pull request replaces "boost::cref(this)" with simply "this".
Note that "std::cref(\*this)" would (likely) also work, but there is no point to adding the overhead of a function call for the *possible* saving of a pointer copy, especially if it complicates the code.