Move classes related to input method to com.android.settings.inputmethod

- Updated proguard.flags

Change-Id: I198761b0f0ad5288c8c807a7a3c2e965731fcee5
diff --git a/proguard.flags b/proguard.flags
index acda9aa..457972c 100644
--- a/proguard.flags
+++ b/proguard.flags
@@ -6,3 +6,4 @@
 -keep class com.android.settings.deviceinfo.*
 -keep class com.android.settings.bluetooth.*
 -keep class com.android.settings.applications.*
+-keep class com.android.settings.inputmethod.*