Comparison of service listener objects is buggy on VS 2008

[saschazelzer]

For Visual Studio 2008, a custom functor implementation is used for service listener objects (instead of std::(tr1)::function). The target() method returns different values for different service listener objects pointing to the same member function, which leads to mismatches when removing a previously registered member function from the listener registry.

[saschazelzer]

In issue #7 the custom functor implementation was removed and std::function is used on all platforms. This also replaced the buggy target() method with the C++11 std::function equivalent.