settings: Make mobile settings a first-class citizen

 * Nobody likes carriers, but let's not bury these settings behind
   10 layers of indirection. Many users (like me) who travel often
   will need to access these options frequently.
 * The top level switch disables mobile data.

Change-Id: I1bd4d1116a2c73832230d66c94df2c3c0aacf698
Merge branch 'cm-11.0' of git://github.com/CyanogenMod/android_packages_apps_Settings into cd-4.4