Populate the subject line with the item/page title when sharing by email

Hi

Please can you consider incorporating this, or something like it, into a future release. It's handy to have the subject pre-populated when sharing links with people and is also useful when using share via email to [add to services like Pinboard](https://pinboard.in/howto/#post_by_mail) etc. I did see there was an [earlier pull request](https://github.com/Xuzz/newsyc/pull/94) about something similar, but I think that one was adding to the message body rather than the subject.

Screenshot as an example of what this looks like in the message composer:

![ios simulator screen shot 26 jan 2014 16 31 16](https://f.cloud.github.com/assets/30024/2004379/0d0af9e8-86a9-11e3-9ad1-e3340a4ff5de.png)