Helper function for cuepoint sub type
Handle cue points by subtype

Dual screen - show slides, do not show chapters.
Chapters - show both slides and chapters.
Both plugins do not store the cue points data now, but always refer to
current cue point as it arrives from the cue points manager.
Add cue point object enums
Merge pull request #1261 from kaltura/thumbCuePointsSubType

Thumb cue points sub type