Created by: reyoung

• min_pool_size would be infinite by default.
  • add unittest for min_pool_size
• Fix bug in can_over_batch_size
  • add unittest for can_over_batch_size
• Add DEFINE_PROVIDER_EX
• Add default value of should_shuffle
  • When training, the default value of should_shuffle is True.
  • When testing, the default value of should_shuffle is False.
  • User a set a provider should_shuffle or not by pass it to @provider
  • should_shuffle can handle a list of value, not just boolean
• Add input order mapping by using name
  • Add unittest
• Add check to check input format.
  • Default is close for speed reason.
  • User could stop train when check error, or continue train without this train sample.
• use deque instead of vector in generators pool, make erase generator faster.
• Add chinese/english documentation
• Make should shuffle = false in unittest
• Add python files to depends.