Video support added.

[engasix]

SKPhotoBrowser is a beautiful tool which save million of lives, only thing which I was missing is the video support, I tried my level best to write code following the same footprint, I hope my pull request will be accepted and I will become part of the community

[engasix]

Waiting for being reviewed!

[tommyming]

@engasix sorry for the awaited late reply.

May I know the purpose of adding video support? Since this repository mainly provides photo browsing options.

Thanks and waiting for your reply!