Addition of non-trivial examples.

Maybe add some non-trivial examples to the docs, as to many folks it will not be immediatley aparent what a powerful concept streams are.

Something like fetching data from one or more sources (xhr, json file?) then forking, parsing, combining, maybe generating some html elements.

I add this issue partially as a note, hopefully I will get some time to contribute some examples.

Related to https://github.com/caolan/highland/issues/28