1. Update the codes of machine translation sample. The current version is the same with NiuTrans.NMT.
2. Update the XList class.
3. Bugs fix.

Support fp16 data type for more operations and fix the minor errors.  (Don't use this! It's an incomplete version)

2. fix the bug of onehotandindex
3. modify the data initilization of transformer
4. add the DumpFormat (need reimplement)

1. Enable the isGradEfficient;
2. Adjust global memory size.

Allocating the global memory pool when it is requested.

1. Global mem mode updated;
2. XTensor function updated to v2 interface;
3. Transformer model updated to v2 interface;
4. FNNLM bug fixed;
5. Other little bugs fixed.

2. Add MemManager class to manage the memory;
3. Use the new version XList;
4. Add a new interface to create Tensor;
5. Apply MemManager to FNNLM.

1. add dropout function 2. add some function in tensor/core/math/unary file 3. merge with xiaotong-working branch

1. Bug fixed; 2. Support abs, sign, convert data type(float <->int) ;3. Merge with xu and xiao branch