[latexrefman] picture and its subtopics

[Hefferon, Jim S.]

I added examples to the picture environment.  I also adjusted the wording, particularly around coordinates.  I also added the remark that typical new docs would use TikZ or some other system, rather than hack integral slopes.

I added some menu items (qbezier and graphpaper, I think).  I added examples to most of these items, and some edge cases.  Found out that \line(0,0){...} acts like \line(0,1){...}.

Jim

-----------
Emoluments.  Noun.  A salary, fee, or profit from employment or office,
as when a US President arranges to have the US government pay a Chinese company despite that it is under official US sanctions, and in return the Chinese government invests millions in a golf course being developed that president.