V1.5: Fix some php warnings and VM3 backend / db upgrade warnings

Makefile

 BASE=buyer_assign_group
 PLUGINTYPE=vmcustom
 ZIPBASE=opentools_vm2
-VERSION=1.4
+VERSION=1.5
 
 PLUGINFILES=$(BASE).php $(BASE).script.php $(BASE).xml index.html
 

buyer_assign_group.xml

@@ -6,7 +6,7 @@
     <authorUrl>http://www.open-tools.net/</authorUrl>
     <copyright>Copyright (C) 2013-2014 Reinhold Kainhofer. All rights reserved.</copyright>
     <license>http://www.gnu.org/licenses/gpl.html GNU/GPL v3+</license>
-    <version>1.4</version>
+    <version>1.5</version>
     <description>VMCUSTOM_BUYER_GROUP_DESC</description>
     <files>
         <filename plugin="buyer_assign_group">buyer_assign_group.php</filename>