[Checkers] "Creating a checker" section of Checker Framework manual

[Michael Ernst]

Jeff-

> A possible solution might be to have q quick start section that
> just showed how to do something simple that didn't try to do everything.
> Something that shows how easy it is to do easy things.  Then it wouldn't
> matter if the later sections went into more detail about less common
> things.  The example could even be non-null without some of the more
> advanced features (such as the control flow stuff).

OK, this is a great suggestion.  The existing checkers are too large to
include in the manual, but a stripped-down version of one would be OK.

I'm not sure when we will get to this, but I'll put it on my to-do list.

                    -Mike