d3d9: Trace the contents of query results.
d3d9: Get(RenderTarget|FrontBuffer)Data have side-effects.

Often these are used just to read data, but the destination sources
can be reused to upload other textures, so it is important that
we honour these calls.
retracediff: Use -log2(rel_error) for numpy images too.
retracediff: Dump PNGs for numpy images too.
Implement --samples=N glretrace flag for X11 GL_ARB_multisample

Implementation for EGL, Waffle and WGL yet to be done.
gltrace: Fix the computation of image sizes.

The size, instead of being computed as

  image_height * row_stride

should actually be

   size_of_first_row + (image_height - 1) * row_stride

as tsondergaard explained in issue #208.
gltrace: Add support for NV_framebuffer_blit.
glretrace: Destroy Context only once via glXDestroyContext

Handling adapted from retrace_wglDeleteContext
qapitrace: ignore supporting files generated by qtcreator

When using qtcreator for build/debug, qtcreator creates miscellaneous
helper files that don't need to be seen by git.

Signed-off-by: Lawrence L Love <lawrencex.l.love@intel.com>
Update GL/glext.h which has a modified argument list for glClearNamedBufferSubDataEXT.
glws_waffle: Support shared contexts.
glretrace: Default to PROFILE_ES2 for EGL.

It should the most common profile for EGL.

Suggested Chad Versace, was quick workaround for issue #197.
md5: Add MD5 library.

From http://www.fourmilab.ch/md5/ .
glretrace: Add '--snapshot-format=MD5' option that allows write image MD5 to a text format file.

Collecting MD5 is obtained based on raw buffer.  Rendering results are
reproducd accurately.  Creating .txt in place of PNG Format, that would
save more disk space and run faster.

Reference command:

    glretrace  --snapshot-format=MD5  -s /tmp/MD5.log  smokinguns.trace
md5: Fix gcc warning.
retrace: Document MD5 snapshot format.
retrace: Make --snapshot-format=MD5 work as documented.

--snapshot-format is the standard output format. -s is the prefix, not
the actual filename.

That is, for MD5 one should do:

  ./glretrace --snapshot-format=MD5 -s - app.trace
image: Fix bug in RAW image output.
image: Simplify MD5 calculation and output.

No intermediate buffer.
image: Avoid snprintf.

Fixes MSVC build failure, as MSVC only defined _snprintf.