Plaintext endpoint requires you to be logged in

The plaintext endpoint doesn't work if you're not already logged in with that browser. This means it doesn't work out of the box with curl, or in an incognito window.

```
soso@virgo ~ % curl "http://www.feedlark.com/plaintext?token=yes_i_have_a_token&username=noah" 

// failed to load your feeds. No data was received from the server.
```
