Reset optind to 1 before parsing options

See merge request !56

Normally the system is already doing this for us. In the MPI simgrid
execution case, however, depending on the enabled optimizations for memory,
libc may not be privatized, to save the memory that would be needed for its
duplication, and to avoid the potential headaches brought by several libcs
running in the same process. The first process would then inrease optind,
and other processes would start with optind already increased.

Timing/options

See merge request !53

Diagonal copy support

Closes #33

See merge request !54

Propose a second more complete patch to Fix #38

Closes #38

See merge request !52

Integration of hierarchicah householder reduction trees

See merge request !47