image: Fix PNM dumping for 2/4 channels.
image: Write the scale factor / endianness line for PFM too.
image: Yet another fix for the PFM dumping.
retracediff: Support floating point images.

Via numpy.
image: Non-standard PNM format variant for 4-float images.
d3dretrace: Make --driver work correctly on DXGI1.1

Need to intercept IDXGIFactory1::EnumAdapters1 too.
retracediff: Dump mismtached float images to stdout.

Should have an option in the future, as it will be too verbose in general.