add examples showing > 1 argument in filter

[tedder]

This is implied but poorly documented. A few examples make it clear.

The first example, "select odd", was already duplicated- I don't know why.

[davidism]

I'd like to get #665 cleaned up and merged so that we can show < and == (or lt and eq) instead of the long names. But I do like this overall, so I'll merge it now.