Control Systems: HP prime app, now with frequency, time domain and root locus plots

[hata]

Hi Archanus and FrankP

I confirm: moving the two small CAS routines (at the end of the Control Systems App code) to a separate program is sufficient to make the App behave correctly on my Samsung 9+ smartphone virtual HP Prime calculator (as said, I never had this issue on my Windows 10 virtual calculator or with a HP Prime).
No other actions are necessary (no renaming, no adding of EXPORT keywords, ...).

So, one of these days I'll release a new version, but in the meantime everyone should be able to make this small adaptation (needed for virtual calculators only).

I really appreciate your feedback and suggestions (and the fact that you like the App, of course :-) ).

Best regards