* First pr of paddle slim.
1. Add framework of paddle slim
2. Add filter pruning strategy
test=develop

* Rename unitest to tests.
test=develop

* Add prettytable into requirements.
test=develop

* Change in_nodes and out_nodes to odered dict.
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* Remove distillation.
test=develop

* Fix API.spec
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* Fix unitest.
test=develop

* Fix unitest in windows.
test=develop

* Fix unitest in windows.
test=develop

* Fix unitest.
test=develop

* Hide some functions.
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* Fix python import in python3.5
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* Fix compress pass.
test=develop

* Fix unitest of test_dist_ctr.
test=develop

* Enhence flops.

* use os.path.join

* Fix pickle for python3
Fix log and comments.
test=develop

* 1. Remove feed_reader in compress pass
2. Fix cache reader
3. Rename CompressPass to Compressor
4. Add comments for distiller optimizer
5. Remove unused pruner currently
6. Add some comments.
7. Change API.spec
test=develop

* Fix pruning in python3.
test=develop

* Fix unitest in python3.
test=develop

* Fix format in python3.
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* Add moving average absmax op in quantilize-aware training.

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test=develop

* Init slim.

* Remove distillation demo.

* Fix import errors.
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* Fix some issues.
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* Fix configs.
test=develop

* Modify API.spec.
test=develop

* Fix format.
test=develop

* Fix format.
test=develop

* Add some comments.