glapi: use GL_ or GLX_ prefix for all category names.

This patch standardizes the category names used in the glapi XML files
to begin each extension name with the prefix "GL_" or "GLX_".  There
is no functional change, because these category names are not used in
the generated code.
Mark GLX extensions as window_system="glX".  TODO: test
glapi: annotate XML with deprecated="3.1" for deprecated functions.

Future patches will use this annotation when code generating
_mesa_create_exec_table(), to determine which functions should be
skipped in core contexts.
glapi: annotate XML with exec="skip" for unimplemented functions.

Future patches will use this annotation when code generating
_mesa_create_exec_table(), to determine which functions should be
skipped because they aren't implemented by Mesa.
glapi: annotate XML with exec="dynamic" for dynamically dispatched functions.

Future patches will use this annotation when code generating
_mesa_create_exec_table(), to determine which functions should be
skipped because Mesa dispatches them differently depending on GL
state.
glapi: annotate XML with exec="loopback" for loopback functions.

Future patches will use this annotation when code generating
_mesa_create_exec_table(), to determine which functions should be
dispatched to functions in api_loopback.c.
glapi: annotate XML with exec="{es,check}" special for GLES1 functions.

Future patches will use this annotation when code generating
_mesa_create_exec_table(), to determine which functions should be
dispatched to ES-specific implementations.  exec="es" indicates that
the ES-specific implementation has a name beginning with "_es_"
(e.g. _es_QueryMatrixxOES), and exec="check" indicates that the
ES-specific implementation has a name beginning with "_check_"
(e.g. _check_GetTexGenxvOES).
glapi: annotate XML with desktop="false" for GLES-only functions.

Future patches will use this annotation when code generating
_mesa_create_exec_table(), to determine which functions should be
skipped when the API is desktop GL.
glapi: Annotate XML with function name suffix anomalies.

When the XML lists one or more GL api functions as aliases for another
GL function, the mesa function that implements the functionality is
usually named after the canonical version of the function (the one
that is the target of the aliases).  For example, FogCoordd is listed
as an alias of FogCoorddEXT, and the Mesa function implementing the
functionality is called loopback_FogCoorddEXT.

However, there are exceptions.  For example, Enablei is listed as an
alias of EnableIndexedEXT, but the Mesa function implementing the
functionality is called _mesa_EnableIndexed.

To account for these anomalies, this patch annotates the XML with
"mesa_name" attributes, which describe how to adjust the function name
to find the corresponding Mesa function.

For example:

  <function name="EnableIndexedEXT" mesa_name="-EXT">...</function>
  <function name="IsProgramNV" mesa_name="-NV+ARB">...</function>

means that EnableIndexedEXT is implemented by a Mesa function called
_mesa_EnableIndexed, and IsProgramNV is implemented by a Mesa function
called _mesa_IsProgramARB.

Future patches will use this annotation when code generating
_mesa_create_exec_table(), to determine the name of the Mesa function
that should be stored in each dispatch table entry.
WIP: De-static loopback functions.
WIP: de-static _mesa_Accum
WIP: de-static dlist functions
WIP: de-static drawpix functions.
WIP: de-static feedback functions.
WIP: de-static eval functions.
WIP: de-static pixel functions.
WIP: de-static rastpos functions.
WIP: de-static texgen functions.
WIP: de-static colortab functions.
WIP: de-static convolve functions.