Added functions to take screenshot after a delay, and ability to save it
Added functions to take screenshot after a delay, and ability to save it

hejunbinlan/BFKit-Swift,FabrizioBrancati/BFKit-Swift,mjasa/BFKit-Swift,jam891/BFKit-Swift,FabrizioBrancati/BFKit-Swift,jam891/BFKit-Swift,FabrizioBrancati/BFKit-Swift,mjasa/BFKit-Swift,hejunbinlan/BFKit-Swift,jam891/BFKit-Swift,mjasa/BFKit-Swift,hejunbinlan/BFKit-Swift