switch to using SysListHandle::systematicsVector() instead of for-each

On request of @jburr to make this easier to understand and teach for beginners. Note that this involved a fair amount of whitespace changes to make the for-body indentation consistent with the rest of each file.

Note to shifter: This is actually a fairly straightforward update which looks very large due to the whitespace changes. It ought to be helpful to select the option to ignore white-space changes.