preventing WPSInitializer from producing unecessary event traffic

When working on a configuration/catalog listener I noticed that for a single event (say add a new catalog catalog object) many events are generated. Tracking it down I found that WPSInitializer produces events when it doesn't need to. The pull request makes it so that:

1. the initializer only does its think on post global change, rather than both pre and post
2. the initialzier only saves back the WPSinfo config if something actually changes