Relax driver requirement for unused update-after-bind bit for uniforms. The executable dflop.exe enables Vulkan validation.

The original paper assumes fully opaque color values, but it is sometimes useful to compare differences in images that possess an alpha channel. FLOꟼ accommodates this by detecting the presence of the alpha channel and scaling the Yy component in linearized Lab space prior to the constrast sensitivity filters.

Full Changelog: v1.618...v1.6180

NOTE: Version numbers converge to phi. I will likely not bother with semantic releases or anything fancy like that

Add HDR support

• HDR images may be loaded as EXR images
• When HDR images are analyzed, an exposure and tonemapping operator is
  needed to convert to LDR ranges
• Added support for ACES, Reinhard, and Hable tonemapping operators
• Added exposure slider control (specified in log2 stops)

Alpha build (Windows only).