Basic Trim + Crop Support

[wifl2k]

The only thing missing is a lightweight trim feature to reduce video length (I use a lot of weird video files and Screenbox is great for opening them but not for trimming dead space out of them without re-exporting in a third party video editor.

This is my single gripe with Screenbox so far.

Cropping to different standard aspect ratios and freeform options would also be a plus but first party trimming for me's a pretty big feature I'd love to see added