bugfix: cannot set sample_type 4 (#5)

Fix conda dependency

Description for something_to_json tool

Description for ucf101_to_json tool

Description for video_folder_json tool

Ignore files generated by OS

hmdb annotation making tool (#2)

Help text and readme

Fix bug in annotation making

The example dataset can load number of classes from json file

Remove error_list parameter

Close the dataset

Add continuous sample mode

Get duration by ffmpeg

dev env