Missing items for takeScreenshot in GlobalActions

 Changes to be committed:
	new file:   core/res/res/drawable-hdpi/ic_lock_screenshot.png
	new file:   core/res/res/drawable-mdpi/ic_lock_screenshot.png
	new file:   core/res/res/drawable-xhdpi/ic_lock_screenshot.png
	modified:   core/res/res/values/strings.xml
	modified:   policy/src/com/android/internal/policy/impl/GlobalActions.java
Some more missing items for screenshots in power menu

Changes to be committed:
modified:   policy/src/com/android/internal/policy/impl/GlobalActions.java