* colorthres.c: validate input chroma.
 * erase.c: fix bluring application limit (prevents out of bounds access).
 * gaussianblur.c: validate input chroma and add planar YUV 4:2:2 support.
 * psychedelic.c: check image_Convert return value (it fails for I422 which would then trigger a segfault due to a NULL pointer being dereferenced).
 * rotate.c: validate input chroma, add planar YUV 4:2:2 support and misc code fixes or simplifications.