Move make_unique to its own header file

Rebuilding the entire project after touching util.h gets old fast.
Remove -Wno-variadic-macros from CXXFLAGS

It's no longer nonstandard in C++11.
Use lambdas rather than std::bind(std::ref(Signal)) for signal forwarding
Remove a pointless ++ and make stuff const
Update the start sample between blocks in the ram audio provider correctly