Extended the warnings and exhortations.
Extended the warnings and exhortations.

I took a number of the comments and suggestions from https://wiki.umn.edu/UMMCSci/CLabNotes and added them at the start of the "Problems" section.
UMM-CSci-Systems/C-Lab-Starter,UMM-CSci-3403-Fall-2017/lab-3-c-programming-arrays-kaisong,UMM-CSci-3403-Fall-2017/lab-3-c-programming-arrays-kaisong,UMM-CSci-Systems/C-Lab-Starter