Merge branch 'feature/Astat-gemm' into 'master'

cmake_modules/local_subs.py

compute/pzgemm.c

compute/pzgepdf_qdwh.c

compute/zgemm.c

control/compute_z.h

control/descriptor.h

doc/user/chapters/using.org

include/chameleon/constants.h

include/chameleon/runtime_struct.h

include/chameleon/tasks_z.h

runtime/CMakeLists.txt

runtime/openmp/codelets/codelet_zgemm.c

runtime/openmp/codelets/codelet_zgersum.c

runtime/openmp/control/runtime_options.c

runtime/parsec/codelets/codelet_zgemm.c

runtime/parsec/codelets/codelet_zgersum.c

runtime/parsec/control/runtime_options.c

runtime/quark/codelets/codelet_zgemm.c

runtime/quark/codelets/codelet_zgersum.c

runtime/quark/control/runtime_options.c