up max devices to 6

Closes #70
// FREEBIE

pom.xml

@@ -94,7 +94,7 @@
         <dependency>
             <groupId>org.whispersystems</groupId>
             <artifactId>websocket-resources</artifactId>
-            <version>0.4.0</version>
+            <version>0.4.1</version>
         </dependency>
         <dependency>
             <groupId>org.whispersystems</groupId>

src/main/java/org/whispersystems/textsecuregcm/controllers/DeviceController.java

@@ -62,7 +62,7 @@ public class DeviceController {
 
   private final Logger logger = LoggerFactory.getLogger(DeviceController.class);
 
-  private static final int MAX_DEVICES = 4;
+  private static final int MAX_DEVICES = 6;
 
   private final PendingDevicesManager pendingDevices;
   private final AccountsManager       accounts;