Add the ability to crop a video

[naamapps]

Hey, really nice package!

I was wondering if it's possible for you to add the ability to crop a video? Like cropping an image, you show the video with a video player (better_player, video_player, etc...), while being able to pan and zoom the video.

You can make another widget (CropVideo) that accepts a video file. When wanting to actually crop the video, you call the function VideoCrop.cropVideo. Maybe add a function like VideoCrop.sampleVideo to make it a better resolution before cropping.

Please consider adding this feature. Thank you!