removing pthread from tutorial cmakelists. Not being used.
removing pthread from tutorial cmakelists. Not being used.

Abasyoni/dynet,kamigaito/cnn,Peilun-Li/dynet,cherryc/dynet,Abasyoni/dynet,Peilun-Li/dynet,Peilun-Li/dynet,mitchellstern/dynet,cherryc/dynet,kamigaito/cnn,mitchellstern/dynet,cherryc/dynet,Abasyoni/dynet