updated jamfile to build on cygwin
updated jamfile to build on cygwin

mildred/rasterbar-libtorrent,mrmichalis/libtorrent-code,mildred/rasterbar-libtorrent,mrmichalis/libtorrent-code,mildred/rasterbar-libtorrent,mrmichalis/libtorrent-code,mrmichalis/libtorrent-code,mildred/rasterbar-libtorrent,mrmichalis/libtorrent-code,mildred/rasterbar-libtorrent,mildred/rasterbar-libtorrent,mrmichalis/libtorrent-code