"Add compact=True flag to json.dump/dumps"

Oh, fun, I implemented exactly this option in my perf project. Extract:

        def dump(data, fp, compact):
            kw = {}
            if compact:
                kw['separators'] = (',', ':')
            else:
                kw['indent'] = 4
            json.dump(data, fp, sort_keys=True, **kw)

So I like the idea of moving the compact=True feature directly into the json module ;-)

(I don't propose to change the default to indent=4, that's a personal choice ;-))