1. Add switch function for switching image dimensions order
2. Add CpuMatrix::backwardSoftmax function
3. Add pixel softmax layer, python wrapper and grad_test

For example:
layer.printer(input=[x, y], format="x=%s y=%s")

Also remove active_type argument for many layers in config_parser.py because it is automatically
handled by LayerBase.

No longer need to specify target_inlinks or is_seq.

No longer need to use SubsequenceInput. The framework will detect.

User can provide an initializer in ParamAttr. The initializer will be called when at parameters.create().

correct a typo

optimize code

fix a bug

change argument name of data_type.integer_value/integer_value_sequence to ele_range, add documentation.