Added a simple style for the welcome view layout, to better support layout on phones in landscape. Fixes #483

Also changed blog settings activity to not be a singleTask since
there's no blog selector in the actionbar any longer.
Don't try to save blog settings if it was just deleted :)

Set WordPress.currentBlog if its settings were changed.
Hide format bar after adding media. Fixes #494

Also added margin to bottom of post editor so that the format bar will
fit for devices that don't have a soft keyboard.
Also hide format bar when canceling media selection.