This adds or changes binding/location decorations in 100s of shaders.
It also allows more output (spv.register.autoassign.rangetest.frag)
due to allowing ioMap() to fail.
Also, remove assumption that if something is opaque that it
must be in the UniformConstant storage class.
This allows function declarations to know all parameters will
be in the Function storage class.
Name mangling did not account for the vector size in the template type of a texture.
This adds that. The mangle is as it ever was for the vec4 case, which leaves
all GLSL behavior and most HLSL behavior uneffected. For vec1-3 the size is added
to the mangle.
Current limitation: textures cannot presently be templatized on structured types,
so this works only for vectors of basic types.
Fixes#895.
