It add loss scale property as model common property.

Signed-off-by: Jiho Chu <[email protected]>

This PR enables the loss scale factor in Weight.
. Change the WeightSpec to incluide the loss factor
. Add LossScaleForMixed Property as an layer common property, so that
  it can set the scale factor in initContext.
. Add Loss Scale in initContext
. Set the LossScaleForMixed Property when there is LossScale Model
  Property

Resolves:

**Self evaluation:**
1. Build test:	 [X]Passed [ ]Failed [ ]Skipped
2. Run test:	 [X]Passed [ ]Failed [ ]Skipped

Signed-off-by: jijoong.moon <[email protected]>

This PR split the Variable and Gradient Dim in Var_Grad and Weight.
By this way we can set different Variable Type and Gradient in Wegiht.
. add dim_g for gradient in WeightSpec.
. manager need to update to support WeightSpec.
. Create Tensors according to dim_v and dim_g
. Create Weight chaged in Weight.h

Resolves:

**Self evaluation:**
1. Build test:	 [X]Passed [ ]Failed [ ]Skipped
2. Run test:	 [X]Passed [ ]Failed [ ]Skipped

Signed-off-by: jijoong.moon <[email protected]>

Loss Scale is more like Rigid Property of model, rather than flexible
property.

Resolves:

**Self evaluation:**
1. Build test:	 [X]Passed [ ]Failed [ ]Skipped
2. Run test:	 [X]Passed [ ]Failed [ ]Skipped

Signed-off-by: jijoong.moon <[email protected]>

We will add Var32 Tensor if the Variable Weight is not Full
precision (FP32). This eables the Weight Update with full precision
and only Apply Gradient Process ueses this Tensor. Therefore, the
lifespan of this tensor should be "ApplyGradient".

. Modify TensorPool to generate Weigth considering Mixed Precsion.

**Self evaluation:**
1. Build test:	 [X]Passed [ ]Failed [ ]Skipped
2. Run test:	 [X]Passed [ ]Failed [ ]Skipped

Signed-off-by: jijoong.moon <[email protected]>