Introduce data caching and avoid re-doing modifications in case if no
important parameter changed.

As simulation and deliveries are less critical, run them less often in order
to give processing power to other tasks.

In order to do that, always use logger, and always in real time.
Logger is properly configured.
Then remove -c switch (kept in parameters but doesn't do anything).
Also factor code of whole slapos/grid directory about SlapPopen (now does the
log).

Conflicts:
	slapos/grid/slapgrid.py

The category is destination_section.

Software instance status does not depend anymore on Sale Packing List state.

Software release installation status does not depend anymore on Purchase
Packing List state.

It didn't worked anyway, so we don't care backward compatiblity here.

Sale Order's have to be ordered, as they are created as planned.