ReplyTextField: Autocorrection enabled by default

Closes #2660
Closes #2531

@aerych may i bother you with a violent review?. Two issues, at the price of one Pull Request!

Thanks in advance!

I'm a bit conflicted. This makes sense since we're setting up the view, but with this patch we have the addition of the didSet method.  With the current implementation there doesn't seem like there is a way for the internal UITextArea and ReplyTextView instance to be out of sync, so that's good. Still, I'm wondering if the the property setter should be used so that the property on the UITextView is always set in a consistent way.  Any thoughts?