Search form styling

- CSS (might want to pull to take a look). Just a start, feel free to change around however you want.
    - NOTE: Still don't know what to do with the pictures. I think we should also show the caption some how (from `post.caption.text`)
- Adds two textfields, an initial main one, a corner one
- Error handling for:
     - Hashtags with invalid characters (doesn't allow user to type in)
     - Hashtags that return 400 from IG on first show (i.e. inappropriate ones)
     - Hashtags that don't return anything on first show (e.g. 'asdfafafasfasfsafasfaf')
     - Bad copied and pasted strings
     - Empty textfield
- Unsubscribes from room if user is only one subscribed and he switches to another hash tag
- Fixes first show bug, it was subscribing to the room after the socket event was submitted so first-show pictures were never shown

**TO DO:**
- Figure out what to do with pictures CSS
- Show a modal when AJAX call returns a 400 (right now just a JS alert)
- Show modal to user and reshow the `#first-search-div` when we run out of pictures / aren't getting any update objects for a while