Issues/1171 cleanup post settings

Sorry for the mammoth pull request.  The cleanup of post settings was a little more involved than originally anticipated.

This PR does several things:
- Simplifies PostSettingsViewController and makes it more readable. 
- Removes obsolete code.
- Moves geotagging and featured image functionality into their own view controllers. This makes the experience more consistent with the other items under post settings, i.e. you tap a cell and get a new screen to do the editing. 
- Featured images is better positioned for when we merge in the media library branch

As a part of the changes in this PR, several issues related to featured images and geolocation are resolved:
Fixes #73 - When Geotagging is enabled the “Publish” button is always enabled.
Fixes #237 - Tapping featured image should open up a single view.
Fixes #325 - Prompted to enable location services when already enabled.
Fixes #395 - De-obfuscate the PostSettingsVC for Page vs Post
Fixes #515 - Display fea tured images in post editor larger on iPad
Fixes #593 - Post Settings: Misleading error for Geotagging when user only ever enters existing posts
Fixes #1195 - Geolocation not always set. 
and of course
Fixes #1171 - clean up post settings

I kept most of the current code around featured images intact and moved it to a new controller rather than refactor. The rationale is the work for a refactor has already been done in the media-library branch and we'll reap the benefits once we merge it in. 

Changes of note:
- The password text field for a password protected post appears as its own cell.
- Featured Images and Geotagging have have new cells. 
- Featured images, and geotagging have a detail views.
- You can select a new featured image from the featured image detail view. 
- As soon as you select an image from the camera, or album, it is displayed on screen. 

You can see a gallery of screen changes here:
https://cloudup.com/csyENgHmeOu