Fixed formatting issue in WPMobileStats
Changing a few Mixpanel events on the post settings to be properties.

In order to be more consistent, I changed some of the post settings
related events to be properties on Mixpanel rather than events. This
change is done to be more consistent with the Android Mixpanel
implementation. The events I changed to properties were:
"Settings - Clicked Set Featured Image"
"Settings - Clicked Remove Featured Image"
"Settings - Clicked Add Location"
"Settings - Clicked Update Location"
"Settings - Clicked Remove Location"