* support rcnn bs=2 in cpp infer

* check dynamic shape in padbatch

* replace fluid by paddle

* fix time display in pptracking cpp

* fix timer in bs=2

* update pptracking and mot doc, test=document_fix

* update docs, test=document_fix

* fix notes, test=document_fix

* add doc & move code to cpp

* add check for track_model and det_model