[Checkers] Trailing spaces in Checker Framework source code

[Michael Ernst]

Matt-

> > Let me know when I can take another look at the code.
> 
> I'll try to have it ready by early evening (EDT).

Mahmood asked me to take a very fast look this evening and let him know if
any classes lacked documentation.  I'll try to do that.  Then Mahmood can
regenerate PDF by, say, 10am tomorrow.  (Matt, when we talk at that time,
please remind me to re-print!)  I told Telmo that he had this last chance
to get his changes into the code, too.

                     Thanks,

                    -Mike