Replaced Task.Delay with Task.FromResult

Replaced Task.Delay with Task.FromResult for the methods which don't use
Task inside otherwise
Fixed usage of bmp.Resize parameters

It was using OutputHeight also for the width parameter.
Resize to use NearestNeighbor instead of Bilinear as it is just downscaling
Merge pull request #1 from teichgraf/master

Replaced Task.Delay with Task.FromResult, Fixed bmp.Resize parameter usage