Suggestion: Output File Type as Input

[raggedy-coder]

Great library! I recently came across this problem where the video generated wasn't viewable on Safari so it got me thinking if if's feasible to add another parameter in the mix for situations like these. I didn't test the proposed code, but the idea is there.

Current:
open func mergeVideoWithAudio(videoUrl: URL, audioUrl: URL, outcome: @escaping (Result<URL, Error>) -> Void) {

"\(VideoGenerator.fileName).m4v"

exportSession.outputFileType = AVFileType.mp4

Proposed:
open func mergeVideoWithAudio(videoUrl: URL, audioUrl: URL, outputFileType: AVFileType = .m4v, outcome: @escaping (Result<URL, Error>) -> Void) {

"\(VideoGenerator.fileName)."\(outputFileType.rawValue)"

exportSession.outputFileType = outputFileType