Change terminology to child and parent devices

The "monitor" and "connect to monitor" descriptions may
have been confusing. Changing the terminology to refer to
a child and parent device.

res/layout/activity_start.xml

@@ -44,7 +44,7 @@
         android:layout_alignRight="@+id/textView2"
         android:layout_below="@+id/startMonitorButton"
         android:layout_marginTop="23dp"
-        android:text="Connect to monitor" />
+        android:text="Use as Parent Device" />
 
     <Button
         android:id="@+id/startMonitorButton"
@@ -53,6 +53,6 @@
         android:layout_below="@+id/textView3"
         android:layout_centerHorizontal="true"
         android:layout_marginTop="34dp"
-        android:text="Start monitor" />
+        android:text="Use as Child Device" />
 
 </RelativeLayout>