SYSPISF_ — Improve stereotype names

The stereotype defined in order to support simulation of physical and signal flows might also be used for specifying related system characteristics through a model, independently of any simulation intent.

However, the "Sim" prefix used for each stereotype defined in this profile might discourage such an utilization and so it tends to restrict its domain of application. It's a shame.

Consider using a more neutral prefix like "pisf" or avoiding using the "Sim" prefix for all of the stereotypes. Especially constants are of far broader interest than simulation only (and should event be introduced in SysML to me). The name "Constant" would be convenient. Also, I think that "SimVariable" could be renamed "FlowVariable".

Merge SYSPISF_-3 into SYSPISF_-5

Merge SYSPISF_-3 into SYSPISF_-5