Add an option to change the device hostname (2/2).

This adds an option to modify the device hostname used
in ip resolution. This is useful when connecting to the
android device in a dynamic dhcp environment.

Change-Id: Ibc145b74036617248d4f33c6866cc9c8a8cc8974

Conflicts:
	res/values/strings.xml

 Author:    Alex Avance <aravance@gmail.com>
 Changes to be committed:
	modified:   res/values/strings.xml
	modified:   res/xml/development_prefs.xml
	new file:   src/com/android/settings/HostnamePreference.java