[plt-dev] documentation enhancements

Two things would make the documentation much better
1. Always give the collection/library that a definition is part of. Some 
parts of the documentation say (require ...) at the top but not all do. 
In the end I resort to grep -r to figure out which collection to 
include. Adding the collection name seems like it could be done 
automatically.

2. More examples would help (and yes I said I would write them before 
but now I'm really going to do it) but I can see how some people would 
find them annoying. Hiding them at first behind a div tag and a link 
that unhides them might be a good option. I think this is reasonable 
since the documentation already heavily uses javascript.