1. Supporting efficient propagate and gradient accumulation for backward functions.
2. Update the setData functions.
3. Clean the codes.

Minor error fixed.

1. Support to copy parts of source tensor to parts of target tensor.
2. New unit test for CopyIndex function.

1. Support scalar tensor for Multiply and Div operation;
2. Fix backward bugs in Multiply and Div function;
3. Minor bugs fixed.

New unit test for Sub function.

Minor bugs fixed.

1. Support scalar tensor for Sum operation;
2. Bounds check;
3. GetSumDimIndex function bug fixed;
4. New unit test for Sum function;
2. Minor bugs fixed.

1. Make link for ReduceSumAll function.
2. Fix the memory leak issue.

Use tensor as the bottom implementation and support plain scalar.
Note: DO NOT support the backward for ReduceSumAll function.

1. Initialize and new scalar tensor.
2. Get and set scalar tensor.
3. Add ReduceSum test on scalar tensor.
4. Little bugs fixed.

1. Move the SetAscendingOrder functions from XTensor.*  to core/utilities/SetAscendingOder.*
2. Rename XElement.* files to XCall.*

1. Move the New/Initial/Del Tensor functions from XTensor.* to XElement.*
2. Move IsSameShaped functions from XTensor.* to core/shape/IsSameShaped.*
3. Move CheckData functions from XTensor.* to core/utilities/CheckData.*

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

1. Merge with Huchi branch (replace all requireLink with enableGrad that allows gradient computation for a tensor);
2. Update the global memory size (This may make the memory size a little bit larger than the old version).

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. fixed the bug in the Spread function.  2. add compare and OnehotAndIndex function 3. optimize the code