Features
* Add `__getitem__` method to `EpicVideoDataset` to enable segments to be
retrieved by ID, rather than having to obtain the `video_segments` and filter
by ID.
* Make `idx` arg optional in `VideoDataset.load_frames`, by default we now load
all the frames for the segment, this behaviour is equivalent to
`VideoDataset.load_frames(segment, range(0, segment.num_frames)`
* Support string paths to constructor of `EpicVideoDataset` and `EpicVideoFlowDataset`
* Support test datasets in `EpicVideoDataset` and `EpicVideoFlowDataset`: Simply set
`class_type` as `None` and the video segment's `label` property will be `None`.
* Bugfix: Gulped flow frames were read in a random order (due to the results of
`glob.glob` not being sorted lexicographically), so if you have used a version
prior to 1.5.0 you should discard your gulped flow, and regulp using the fixed
adapter - our sincere apologies for the inconvenience caused.
**WARNING: People who have gulped flow**:
If you have used any previous version of the library to gulp flow,
then you should discard that flow and regulp the flow due to the previous
version of the adapter reading frames in an unsorted manner resulting in
flow segments within the gulp file being randomly shuffled.