Advanced Optional Methods demo please

[suntong]

Please add some demo of those Advanced Optional Methods. I want to know how to make use of them for something like this -- look at the doc for PieceShaper

E.g., for SqrapePostFlight method, could you add another example based on your examples/tweetgrab.go file for https://twitter.com/GasBuddyDan, and filter/return only tweets that contain "Gas Price Alert" key phrase please? Thx.

[cathalgarvey]

This is very overdue; I'd like to offer better examples and documentation for those methods, yes. I'll leave the ticket open and see when I can return to sqrape to build more stuff on it.