v0.5.1

• 📝 Rewrite documents with mkdocs
• 📝 Add Chinese documents
• ✨ Add predict_top_k_class for classification model to get predict probabilities (#146)
• 🚸 Add label2idx, token2idx properties to Embeddings and Models
• 🚸 Add tokenizer property for BERT Embedding. (#136)
• 🚸 Add predict_kwargs for models predict() function
• ⚡️ Change multi-label classification's default loss function to binary_crossentropy (#151)