Save settings#32

It would be convenient if some settings could be saved, so that we don’t have to change them with every new Phi session! Such settings to be saved could include “long-lived” ones, such as:
Show labels, Show tooltips, Workspace units, Set background…(and any others you might suggest?)

Furthermore, these could be grouped under a single window, to keep the remaining, “short-lived’ setting list shorter.

Completed, version 1.7.0