Add list of accounts in Phone Account Settings.

+ Add new constants to define SubId/SubLabels on intent which opens
the call settings.
+ Add an "accounts" preference category to phone account settings.
+ Add preferences to this new performance category for each
subscription.
+ Configure these preferences to launch an intent to start call
settings, containing the id and label of the subscription.

Bug: 18114923
Change-Id: I989bf3480418c9ac003dce677ec7b3585e82a551
diff --git a/res/values/strings.xml b/res/values/strings.xml
index 88020fc..d54b242 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -134,8 +134,9 @@
     <!-- Entry in dialog to "ask first" for accounts when making a call -->
     <string name="phone_accounts_ask_every_time">Ask first</string>
 
-    <!-- Label for heading of the accounts section in the phone accounts settings screen. -->
-    <string name="phone_accounts_accounts_header">Accounts</string>
+    <!-- Label for heading of the per-account settings section in the phone accounts settings
+         screen. -->
+    <string name="phone_accounts_settings_header">Settings</string>
     <!-- Label for invoking phone account selection screen -->
     <string name="phone_accounts_choose_accounts">Choose accounts</string>
     <!-- Label for heading in the phone account selection screen -->