Fixed namespace conflict in C++/CLI.

Closes #533.

Related:

https://github.com/mono/CppSharp/pull/520 cf472f526c

src/Generator/Generators/CLI/CLITypePrinter.cs

@@ -327,7 +327,7 @@ namespace CppSharp.Generators.CLI
 
             names.Add(decl.Visit(this));
 
-            return string.Join("::", names);
+            return "::" + string.Join("::", names);
         }
 
         public string VisitClassDecl(Class @class)

tests/CLITemp/CLITemp.cpp

@@ -14,3 +14,8 @@ void testFreeFunction()
 {
 
 }
+
+void UseFoo::takesFooPtr(Foo* ptr)
+{
+
+}

tests/CLITemp/CLITemp.h

@@ -49,3 +49,11 @@ std::ostream& operator<<(std::ostream& os, const Date& dt)
 }
 
 DLL_API void testFreeFunction();
+
+class DLL_API Foo { };
+
+class DLL_API UseFoo
+{
+public:
+    void takesFooPtr(Foo* ptr);
+};