Add __builtin_popcount* based fast Hamming distance math function
Add and test sum of absolute values math functions for CPU and GPU
Add and test element wise sign math funtions for CPU and GPU
Instantiate caffe_cpu_sign for float and double
Add and test element wise abs math functions for CPU and GPU
Cherry pick mkl_alternate by Rowland Depp in 7e8ef25c7 of boost-eigen
Use macro to simplify element wise cpu math functions
Add and test non-in-place scale math functions for CPU and GPU
Remove mkl_alternate and move the define func macros to mkl_functions
Add signbit math func, simplify GPU defs & instantiations with a macro