BradLarson/GPUImage — pull request #905 by aburgel (2013-03-29 19:05:01+00:00)
Title: Fix GPUImageTwoInputFilter to correctly reset itself

This addresses issue #687.

Its possible for `[GPUFilter setInputText:atIndex:]` to be called with `newInputTexture` set to `zero`. This is not a valid texture name, so this is effectively resetting the input texture. Since that's the case, `hasSetFirstTexture` should not always be `YES`.