* Renamed range update callbacks
We finally settled on
didEnter/ExitDisplayState
didEnter/ExitPreloadState
didEnter/ExitVisibleState
This change is meant to unify the range update methods to relate to each
other and hopefully be a bit more self explanatory.
* Guarantee interface callbacks happen on main.
* move fetchData / clearFetchedData to default implementations
* Move deprecated methods to new deprecated category
* Don't bring in cocoapod change.
* Nits
* Capetalize
* [ASVideoNode] Add delegate method called when the currentItem is set.
* [ASVideoNode] Add videoComposition and audioMix properties to the ASVideoNode.
* [ASVideoPlayerNode] Add new initialiser with videoComposition and audioMix, and forward new delegate method.
* [ASVideoPlayerNode] Forward missing ASVideoNodeDelegate methods.
* Removed play button from ASVideoNode
* Removed play button tests
* added some checks in ASVideoPlayerNode
* added new delegate method for time formats
* changed static string to ASVideoPlayerNodeControlType
* public property for duration
* public method for seek
* new _controlFlexGrowSpacerSpec; used to use flexible space in
controlbar. for example if user does not want to have scrubber, he can
replace it with flexible spacer and duration text node will be kept at
the right edge.