remote_thr.cpp: port pthreads usage to win32 api
include source directory version of zmq.h and zmq_utils.h

this follows what {local,remote}_lat.cpp and inproc_{thr,lat}.cpp do.
add simple Makefile to build with mingw32
Merge pull request #525 from pijyoi/master

remote_thr.cpp: port pthreads usage to win32 api