1. First install dependencies;
    2. Surpport abosulate import.

Add shuffle type of instance_shuffle and batch_shuffle_clipped.

Add image classification models.

update README.md

refactor text classification.

update language model's README

add neural language model.

Refactor the data preprocessor part for DeepSpeech2.

Expand .travis.yml to support docker.

Refactor whole data preprocessor for DS2 (re-design classes, re-organize dir, add augmentaion interfaces etc.).

1. Refactor data preprocessor with new added class AudioSegment, SpeechSegment, TextFeaturizer, AudioFeaturizer, SpeechFeaturizer.
2. Add data augmentation interfaces and class AugmentorBase, AugmentationPipeline, VolumnPerturbAugmentor etc..
3. Seperate normalizer's mean and std computing from training, by adding FeatureNormalizer and a seperate tool compute_mean_std.py.
4. Re-organize directory.

Support variable input batch and SortaGrad.