2D thread distribution for multi-threaded GEMMs

CMake improvements

Allows maximum use of available cores if one of M and N is small and the other is large.

Stride calculation fix copied from https://github.com/wernsaar/OpenBLAS/commit/88900e1

If OpenBLAS is built using add_subdirectory(OpenBlas) as part of another project
then the paths set by CMAKE_XXX_DIR are relative to the parent project
and not the OpenBLAS project.

Disable CBLAS and LAPACK.

Instead of generating separate object files for each permutation of
defines for a source file, GenerateNamedObjects now writes an entirely
new source file and inserts the defines as #define c statements.

This solves a problem I ran into with ar.exe where it was refusing to
link objects that had the same filename despite having different paths.

Added zherk_k sources to driver/level3.

This will generate obj files for SINGLE/DOUBLE/COMPLEX/DOUBLE COMPLEX.

MSVC doesn't inmplement C99, so can't use the inline keyword. __inline
appears to work in MSVC and GCC.

It sets DBLAS_OBJS directly to save a bunch of list appending in the
CMakeLists.txt files.

The level3 object names should now be correct.

Fixed the code array not getting reset on subsequent AllCombinations
calls.

Since the objects are the same, could generate SINGLE/COMPLEX/etc here
without having to rewrite all the object enumeration code again.

This function takes a set of sources and a set of preprocessor
definitions. It will iterate over the sources and build an object
file for each combination of preprocessor definitions for each
source file.

Added a rather convoluted CMake function to find all combinations
of a given list. This will be useful for the object files that are
compiled multiple times with different combinations of preprocessor
definitions.

Signed-off-by: Timothy Gu <timothygu99@gmail.com>