more consistent name,
 refactor stbi_load_main to preserve old code,
 support float HDR path,
 minor bugfix

bump version and update credits;
minor whitespace changes;

GCC 4.7 gave the warning "signed and unsigned type in conditional
expression" because the ternary operator mixes signed and unsigned
integers. Fixed by casting to unsigned inside the "if" branch instead
of casting the result of the entire conditional.

This fixes two things. First, the logic to disable SSE2 on
GCC unless "-msse2" was not specific enough, and ended up
disabling SIMD support on NEON targets entirely. Shuffle
the detection logic around to make that bit x86-specific.

Second, 32-bit MinGW assumes 16-byte aligned stacks, but this is
not in the Windows ABI and hence DLLs and callbacks don't
necessarily provide it. This caused a crash.

This can be fixed by providing the right command-line option,
which we have no control over. As a compromise, disable the SSE2
path on MinGW unless a specific #define explained in the comments
is set. That way, we default to safe (never-crashing) behavior
unless the user explicitly signals they know what they're doing.

fix incorrectly-named assert, attempt to fix (char) cast warning (tricky since char's signedness is unknown)

this variable was causing a warning while compiling with gcc.

tweak docs

Also ran a bunch of test cases to make sure the IDCT and H2V2
resamplers were correct.

Put progressive JPEG AC decode logic back the way I wrote it originally (I changed it to match jpgd when I was trying to figure out why it didn't work);
add STBI__ prefixes to internal SCAN_ enum;
strip unused function arguments for progressive funcs;
tweak release notes;
forget to git commit frequently so these would all be in their own commits;

stbi__ prefix on two functions that were missing it

fix long-standing bug where gifs were just broken AFAICT

tweak credits
tweak revision history
remove trailing whitespace

fix a few old error messages

some documentation cleanup

add missing STBIDEFs to a few functions;
update documentation with full 1.49 info even though most isn't implemented yet

  support using inline asm for cpuid

YCbCr:
  switch SSE code to constants that match old C;
  create C version that is same as SSE;
  tiny optimization(?) of SSE