#788 loadshapes are not compatible with schedule skews

[Jason Fuller]

When shapes are used to describe behavior, the schedule skew is not taken into account. For example, this DOES shift the schedule by 2 hours:

object plugload {

schedule_skew 7200;
name refrigerator;
installed_power 1 kW;
demand my_schedule;
power_factor 1.0;
power_fraction 1.0;

};

while this does not

object plugload {

schedule_skew 7200;
name refrigerator;
shape "type: analog; schedule: my_schedule; power: 1";
power_factor 1.0;
power_fraction 1.0;

};