Add subscribe to new feed button + small fix

Hi,

I love your toolbar ;)
One thing people which use my ttrss often says is that the "add new feed" link is pretty hidden, so, looking at your toolbar, I said to myself "That's where it belongs to !"
So here is my patch. My icon is not as good as yours but I didn't find better. Surely you can add a prettyer one.

And there was a little bug in a link title, which is fixed now.

Regards