Bug 377332 - Installing incompatible addons (locale, plugin) doesn't show any compatibility warning

p=Dave Townsend <mossop.bugzilla@blueprintit.co.uk>
r=rstrong, sr=beltzner

toolkit/locales/en-US/chrome/mozapps/extensions/extensions.properties

@@ -51,6 +51,8 @@ disabledObsoleteTitle=Old Extensions
 disabledObsoleteMessage=Any old extensions that you have installed have been disabled.
 
 type-32=Multiple Extension Package
+type-16=Plugin
+type-8=Language
 type-4=Theme
 type-2=Extension
 incompatibleTitle=Incompatible %S