Further refactor Telecom and add tests

Complete refactoring Telecom to remove singletons from the core code.

Introduce a unit test that simulates a full outgoing phone call from
start to hangup.

Change-Id: I8b09cac6eb9b6aeeb0aeba5d8ae032b4c303c08d
diff --git a/proguard.flags b/proguard.flags
index e52ac20..357336b 100644
--- a/proguard.flags
+++ b/proguard.flags
@@ -1,4 +1,8 @@
 -verbose
-
-# Keep @VisibleForTesting elements
 -keep @com.android.internal.annotations.VisibleForTesting class *
+-keep class com.android.server.telecom.TelecomSystem {
+  *;
+}
+-keep class com.android.server.telecom.Log {
+  *;
+}