Fix for Makefile on OS X

[pluskid]

On my OS X, the shared libraries of CUDA are placed in CUDA_HOME/lib instead of CUDA_HOME/lib64. Please change the following line from

MSHADOW_LDFLAGS += -L$(USE_CUDA_PATH)/lib64

to

MSHADOW_LDFLAGS += -L$(USE_CUDA_PATH)/lib64 -L$(USE_CUDA_PATH)/lib

[tqchen]

Done

[szha]

This code base has been donated to the Apache MXNet project per #373, and repo is deprecated. Future development and issue tracking should continue in Apache MXNet.