Make view admin open in Safari

By looking at user feedback, it seems having the admin embedded in the
app is often more confusing that helpful.
Fixes missing refresh header on notifications view.

There was a xib for the notifications list view. Redundant since its inheriting from WPTableViewController.  The loaded xib resulted in two UITableViewControllers, one a child of the other.
Removing the xib and calling init instead of initWithNibName:bundle fixes the issue where the refresh header would sometimes appear to be missing when scrolling the extra UITableView.

Also removes a now obsolete xib for the hybrid reader.
Merge branch 'release/3.7' of https://github.com/wordpress-mobile/WordPress-iOS into release/3.7
Fix build warning: unused variable
Fixes an issue where quick post/page + buttons showed the wrong state.

The UITableViewCell was setting the accessory view's highlighted state to YES. Not sure if this is happening in the code somewhere and I couldn't find it or if this is something Apple does by design. Setting the highlighted state to NO when the cell's selection state changes seems to fix the problem.
#1645 Added nil check to settings when adding flags to build files
Fixes layout concerns with the View Admin button.

The view admin button would overlap the view site button, and show up even when the section was closed.
Restores the View Admin cell and populates it with a button. The button intercepts the tap on the row and avoids triggering row selection.
Seems to work well enough tho the button icon dims when pressed and the icons in cells do not.  Minor difference.
Merge branch 'release/3.7' into develop
Don't let the View Admin button's icon dim when tapping.

Props @koke
Adding stats for new reader.
Merge remote-tracking branch 'wordpress-mobile/pr/38' into develop
Merge branch 'develop' of github.com:wordpress-mobile/WordPress-iOS into develop
Store current selection on sidebar

After some changes, `currentIndexPath` wasn't saved for items in section
0.

resolves #40
Merge branch 'release/3.7' of github.com:wordpress-mobile/WordPress-iOS into release/3.7
Fix selection restoration for sidebar
Improve how images are loaded in reader

* Reload images on rotation
* Use aspect fit when a cell image is set. This allows for the image to
  scale up/down after rotation while the right size is fetched
* Reload images when cell is displayed, since cells won't have the right
  size on creation for iPad. resolves #39
Decide to load images depending on scrolling speed

Before this, we loaded reader images only when the table wasn't
scrolling or being dragged unless we had the image ready with the
correct size. This meant that images wouldn't load if you were scrolling
really slow, or even stopped but still had your finger on the screen.

This implementation only prevents image loading if we detect the table
view is scrolling "fast".

After testing, images seem to load almost immediately on WiFi while
performance is still good. I'll have to test on 3G to see if it's good
enough.

see #24
Fixes an issue where simulating pull to refresh tripped isFastScrolling

Setting the table view's content offset, as we do when simulating pull to refresh or dismissing the refresh header, triggers the scrollViewDidScroll: delegate method.
Since the refresh offset is greater than the fast scrolling threshhold the _isFastScrolling flag is set but never cleared since the scrollview is stationary.
The result is that newly added cells do not display their featured images.
Adds a flag that we can check to see if the refresh offset is being set so we can skip setting the _isFastScrolling flag
Improves the pullToRefresh/isFastScrolling patch
https://github.com/wordpress-mobile/WordPress-iOS/commit/4a995c577c63d2fde03d8e0988b1e65d75744d46
Updated stats for Reader.

* Added category to the infinite scroll stat.
* Added "Reader - Unliked Post" stat.