update anomaly detection models docs (PaddlePaddle#316)

* fix metrics test bug and docs error

* fix some spelling errors of anomaly models

* fix some spelling errors of anomaly models

* upgrade of anomaly detection, including (1) adding data check logic (2) supporting category variables in AutoEncoder model (3) supporting adjustment of prediction results according to true labels

* upgrade of anomaly detection, including (1) adding data check logic (2) supporting category variables in AutoEncoder model (3) supporting adjustment of prediction results according to true labels

* upgrade of anomaly detection, including (1) adding data check logic (2) supporting category variables in AutoEncoder model (3) supporting adjustment of prediction results according to true labels

* upgrade of anomaly detection, including (1) adding data check logic (2) supporting category variables in AutoEncoder model (3) supporting adjustment of prediction results according to true labels

* upgrade of anomaly detection, including (1) adding data check logic (2) supporting category variables in AutoEncoder model (3) supporting adjustment of prediction results according to true labels

* upgrade of anomaly detection, including (1) adding data check logic (2) supporting category variables in AutoEncoder model (3) supporting adjustment of prediction results according to true labels

* upgrade of anomaly detection, including (1) adding data check logic (2) supporting category variables in AutoEncoder model (3) supporting adjustment of prediction results according to true labels

* update anomaly example notebook

* update anomaly detection models docs