support for dumping summary file to plain text form

[Dusty Mabe <dusty dustymabe com>]

As a normal user I'd like to be able to dump an ostree summary file 
into plain text form without having to learn specifics about the 
binary gvariant representation it is stored in. 

Could we do one of three things:

1 teach the command line tools to be able to parse a summary file and
  dump it as plain text
2 provide a tool that does effectively the same thing
3 store the summary file in a plain text, but still machine friendly
  form (i.e. json or similar) so that all I need to do is "curl" to
  see the details of what is in the file.

I'd prefer 1 or 3 so that I don't have to "find" the tool every time I
want to use it.

Thanks,
Dusty