Adding the author mapping to the feeds.

#4207 
Importing nodes behalf of other uses in CSV is not a problem. The problem i facing is when importing from RSS or iCal: each RSS feed hold the name of the author in a different logic(drupal planet holds it in the title, engadget holds it in <de:creator> tag etc. etc.). in the iCal file from my Google calendar the name of the author is actually an email and it's stored in: ```ORGANIZER;CN=inbaljona@gmail.com```