Move more classes to more specific locations.

Moved .model classes to .base.
Deleted some unused classes.
Moved functional tests into a new .funcitonal package.
Followup to 1450250.

Change-Id: Ic087fe4a014d9179fab3dc6f833aaf73373f9452
diff --git a/src/com/android/documentsui/DirectoryResult.java b/src/com/android/documentsui/DirectoryResult.java
index f7ccc48..32910ce 100644
--- a/src/com/android/documentsui/DirectoryResult.java
+++ b/src/com/android/documentsui/DirectoryResult.java
@@ -19,7 +19,7 @@
 import android.content.ContentProviderClient;
 import android.database.Cursor;
 
-import com.android.documentsui.model.DocumentInfo;
+import com.android.documentsui.base.DocumentInfo;
 import com.android.documentsui.sorting.SortModel;
 
 import libcore.io.IoUtils;