* add multinomial cpu kernel

* fix C++ notype error

* fix windows ci array len error

* let array len be const

* change array to vector

* add cuda kernrl with num_distribution is 1, and not support replacement=False

* add multinomial python api

* support num_distribution different multinomial distributions

* add categorical class

* fix test_distribution enable_static error

* add unittest for different setting of Categorical

* optimize format

* little change

* little change

* add raise error if shape not match, optimize format

* fix windows CI dtype error in concat

* little changes

* little changes2

* change values type to int64

* change values type to int64

* change values type to int64

* increase tolerance

* increase the difference between low and high

* change tolerance of Normal log_prob method

* change probs tolerance to 1e-4

* change tolerance of Normal kl method

* fix _to_tensor method of Distribution class

* Add unittest

* let dtype be consistent with value in log_prob and probs

* fix format

* fix dtype problem and change unittest

* fix dtype of Numpy class in unittest

* add formula for entropy and kl

* change formula

* fix kl formula format

* fix kl formula format 2

* change gt to np in unittest

* optimize unittest format

* delete dumplicate

* delete dumplicate 2

* extract common function used to convert dtype value

* fix sample shape error

* Add unittest

* change assert_allclose to assert_equal

* Add unittest doc

* fix encoding problem

* fixed static module

* solve conflict

* Add Distribution base class, Uniform class and Normal class

* release Distribution class and Normal, Uniform class

* Add Doc args explaination

* save distributions.py and process in distribution.py

* delete useless function in test_distribution

* Add NormalNumpy test class

* Add probs in NormalNumpy

* add distribution to paddle init

* Add Distribution base class and name attribute unittest

* Change Doc

* Change Doc

* adjust format

* Fixed Doc Code

* implement probs and change Variable to Tensor

* Add name for all functions and add name unittest

* support int datatype

* Add dynamic mode

* optimize test_distribution static and dygraph