ENH: naming pyIDI video objects

[domengorjup]

When dealing with multiple different videos, it would be helpful to add a vdeo_name attribute to the pyIDI object. This could either be read from the .cih file's "Comment" entry, the video file name, or input as a new argument to the pyIDI constructor.

This attribute could then be used as a title in the various plots (e. g. show_points) etc.

[jankoslavic]

@itomac I guess this is now handled with the new videoreder, or? @