Tweak CordovaPlugin.initialize method to be less deprecated.

Thinking here is that we need a while for both initialize and
pluginInitialize to exist before plugin authors would bother not using
the deprecated one anyways. Really, no harm in keeping both for some
time.
Merge branch 'master' into 4.0.x (CordovaPlugin.pluginInitialize tweak)

Conflicts:
	framework/src/org/apache/cordova/CordovaPlugin.java