Fix compilation with clang on OSX

Added a Tostring function for type size_t, otherwise
an implicite conversion into (u)int results in ambiguity.
Fix compilation for clang on OSX

C++11 introduces std::bind for binding parameters to functions.
Make clear we want bind from sys/socket.h (global namespace)
by prepending '::'.
Fix compilation for clang on OSX

-std=c++11 activates C++11 but on OSX you need -stdlib=libc++ too
since the default stdlib is too old.
Fix linking for OSX

If dependencies were installed according to the Readme.md boost
libraries are suffixed with -mt.
Also removed unnecessary flag.