Cleanup feed flow and check profile page children initialization

Significant reduction of complexity.

ProfilePage will not call any of its children unless the user is available. This will prevent any of its children from having to check for their props. It will also mean that this.state.user is the consistent check for all child components from now on, which is an easy pattern.

Feed now has a nice flow, since it has a parent flag. It may be possible to dynamically determine the class of the parent component, which I'm waiting on with a StackOverflow post (http://stackoverflow.com/questions/26541400/can-you-dynamically-get-parent-component-classname-in-reactjs)

Feed also no longer passes parameters to setTransactions(). This reduces complexity. To counteract the asynchronous nature of setState(), rather than passing the new filter state to setTransactions(), we can just call componentWillUpdate(), which will only act after setState() has occurred.
This could probably be refactored to this:
```
if (this.state.user) {
  var feed = ...
  var portfolio = 
  ...
} else {
  initialize all to empty strings;
}
```