API Cleanup - rename IConferenceable to Conferenceable.

- Fix 23 api to remove build error.  Conferenceable extends IConferenceable
so they are interchangeable.

Bug: 20165255
Change-Id: I8cb644c7af839b044e197bd1ca519b9d415c9f55
diff --git a/system-api/23.txt b/system-api/23.txt
index 0d34dcf..a3b9601 100644
--- a/system-api/23.txt
+++ b/system-api/23.txt
@@ -29904,7 +29904,7 @@
     field public static final int RINGING = 4; // 0x4
   }
 
-  public abstract class Conference implements android.telecom.IConferenceable {
+  public abstract class Conference implements android.telecom.Conferenceable {
     ctor public Conference(android.telecom.PhoneAccountHandle);
     method public final boolean addConnection(android.telecom.Connection);
     method public final void destroy();
@@ -29938,7 +29938,7 @@
     field public static final long CONNECT_TIME_NOT_SPECIFIED = 0L; // 0x0L
   }
 
-  public abstract class Connection implements android.telecom.IConferenceable {
+  public abstract class Connection implements android.telecom.Conferenceable {
     ctor public Connection();
     method public static java.lang.String capabilitiesToString(int);
     method public static android.telecom.Connection createCanceledConnection();
@@ -29951,7 +29951,7 @@
     method public final java.lang.String getCallerDisplayName();
     method public final int getCallerDisplayNamePresentation();
     method public final android.telecom.Conference getConference();
-    method public final java.util.List<android.telecom.IConferenceable> getConferenceables();
+    method public final java.util.List<android.telecom.Conferenceable> getConferenceables();
     method public final int getConnectionCapabilities();
     method public final android.telecom.DisconnectCause getDisconnectCause();
     method public final int getState();
@@ -29974,7 +29974,7 @@
     method public final void setAudioModeIsVoip(boolean);
     method public final void setCallerDisplayName(java.lang.String, int);
     method public final void setConferenceableConnections(java.util.List<android.telecom.Connection>);
-    method public final void setConferenceables(java.util.List<android.telecom.IConferenceable>);
+    method public final void setConferenceables(java.util.List<android.telecom.Conferenceable>);
     method public final void setConnectionCapabilities(int);
     method public final void setConnectionService(android.telecom.ConnectionService);
     method public final void setDialing();
@@ -30069,7 +30069,7 @@
     field public static final android.os.Parcelable.Creator<android.telecom.GatewayInfo> CREATOR;
   }
 
-  public abstract interface IConferenceable {
+  public abstract interface Conferenceable {
   }
 
   public abstract class InCallService extends android.app.Service {