Require cmake 2.8.5 to avoid inscrutable error messages w/ pre-2.8.5 cmakes

Dependencies/CMakeLists.txt

@@ -1,4 +1,4 @@
-CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
+CMAKE_MINIMUM_REQUIRED(VERSION 2.8.5) # 2.8.5 needed for full URL support
 
 PROJECT(PolycodeDependencies)