SourceFilter is replaceable when Append is called.
BaseSourceFilter is thus introduced for derivation purposes.
Added Nedi quadrupling in MyRenderScript.cs example.
Fixed IsDownscalingFrom/IsNotScalingFrom/IsUpscalingFrom methods.
Changed MyRenderScript.cs example to upscale using NEDI once only by default (with instructions to enable stacking NEDI until past target size).
Removed unused namespaces.
Merge pull request #14 from zachsaw/work

Work