Fix for when no "itunes:owner"
Fix for when no "itunes:owner"

Hi @bobby-brennan, love this package, thank you for creating it.

I've been getting some Typeerrors from feeds which have itunes fields but no "itunes:owner". I traced it to the "decorateItunes" function:

it looks like `json.feed.itunes` is only created if there is an "itunes:owner"; if there isn't an *owner* but there are *other* itunes fields, the loop tries to add the PODCAST_TOP_FIELDS to `json.feed.itunes`, which obviously doesn't exist. So I just added a line to create the property either way.

I doubt my fix is the ideal solution, but it seems to solve the problem for me!
bobby-brennan/rss-parser,bobby-brennan/rss-parser,bobby-brennan/rss-parser