Update for PhoneGap 2.2.0

This updates the plugin for PhoneGap (Cordova) 2.2.0 (and probably
later versions as well). Please note that if you are using this plugin
for one of the later versions of Cordova you need to edit the
config.xml not the plist file.
Merge pull request #3 from sebastian-meier/master

Update to PhoneGap 2.2.0