Allow creating custom dialogs in DialogPreference.

This allows creating non-AlertDialogs while still using the click and
state handling of DialogPreference.

Change-Id: I54fd7d6d6b9f6a49fef1ae95e0178838b3edfa56
Merge "Allow creating custom dialogs in DialogPreference." into cm-10.1
Merge branch 'cm-10.1' of git://github.com/CyanogenMod/android_frameworks_base into jb-mv