Implements blas_dgemm with the help of templates.

The Makefile just became out of date, we can't include the file
libhipeless.cpp in the compilation anymore.
mpihelper.cpp hardcodes the function call, it shouldn't be so.

Code is duplicated in operations.cl because the standard doesn't
support any kind of templates.
mpihelper chooses to run the needed function.
Remakes the Makefile.
Removes unused flags on the Makefile.