[boost] [boost.thread] Experimental alternative TLS implementation

While searching for a method to overcome the intentional memory leak on the windows implementation of tss, I wrote a new shrink wrapped version of tss, for discussion of possible improvements over the current implementation. The proposal will not alter the current interface, but adds the following features: * Completely orthogonal to boost::thread * No memory leaks * Twice as fast for -> operator * Threads may (in principle) live after end of main() Currently this will only work on windows, but it should be possible to port it to pthreads as well with little effort. I have uploaded the file tls_win.zip to the boost filearea on Yahoo. Roland