Fixed the class containing context functions to be unsafe.

Signed-off-by: Dimitar Dobrev <dpldobrev@yahoo.com>

src/Generator/Generators/CSharp/CSharpTextTemplate.cs

@@ -216,7 +216,7 @@ namespace CppSharp.Generators.CSharp
             if (context.HasFunctions)
             {
                 PushBlock(CSharpBlockKind.Functions);
-                WriteLine("public partial class {0}{1}", SafeIdentifier(Options.OutputNamespace),
+                WriteLine("public unsafe partial class {0}{1}", SafeIdentifier(Options.OutputNamespace),
                     TranslationUnit.FileNameWithoutExtension);
                 WriteStartBraceIndent();