(This blog posted was updated with additional information on Oct 23, 2015, Thanks, Vagner!)
The recent updates to PhoneGap have resulted in another change being needed to your configxml.
In Project Properties, add these lines anywhere in the middle of PhoneGap configxml:
<gap:plugin name="cordova-plugin-splashscreen" source="npm" /> <preference name="AutoHideSplashScreen" value="true" />
Without this, your splashscreens will not appear.