[MERGE] file-object based container format

[Andrew Bennetts]

Andrew Bennetts has voted +1.
Status is now: Approved
Comment:
Looks good to me.  I've fixed the BaseReader.__init__ docstring to be 
consistent with your changes, and also added "(introduced in 0.18)" to 
the format string, and submitted this to PQM.

Thanks!

For details, see: 
http://bundlebuggy.aaronbentley.com/request/%3C4683EEFA.6030601%40utoronto.ca%3E