Revert "Fixed RGBA/2_10_10_10_REV & variants ..."

This reverts commit cd028fdeed507bad41b73770619e8b77f254301f.
Revert "Fix issue with GL_UNSIGNED_INT_8_8_8_8[_REV] ..."

This reverts commit 71ea44f8a6086ef11001c47fce3e499f46d8518b.
Add a printf() to show 3 key KTX-file-header fields.

I show whether the endianness is opposite of the system, and what the format
and type of the image are.
Experiments to find real problem.
Revert "Experiments to find real problem."

This reverts commit c825715b22bb12af97867211d31d87c20c739617.
Fix issue with GL_UNSIGNED_INT_8_8_8_8[_REV] ...

I had incorrectly remembered and associated GL_UNSIGNED_INT_8_8_8_8 with
GL_RGBA/GL_UNSIGNED_BYTE.  The correct associated of GL_RGBA/GL_UNSIGNED_BYTE
is with GL_UNSIGNED_INT_8_8_8_8_REV.  The error caused the compoents to be
swizzled in an ABGR fashion.

This commit fixes that problem for both GL_RGBA and GL_BGRA.
Better fix for GL_UNSIGNED_INT_8_8_8_8[_REV] ...

The GL_RGBA/GL_UNSIGNED_BYTE combination is associated with
GL_RGBA/GL_UNSIGNED_INT_8_8_8_8_REV, but I had the values reversed between
those two combinations and the GL_RGBA/GL_UNSIGNED_INT_8_8_8_8 combination.  By
reversing these, many other format-type combinations no longer looked correct
(e.g. a GL_RED image had solid red components and varying alpha components).

I have now tested this across a larger set of KTX files, and things seem to be
good.