Copied the signature and the line number when cloning functions.

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

src/AST/Declaration.cs

@@ -342,6 +342,7 @@ namespace CppSharp.AST
             PreprocessedEntities = new List<PreprocessedEntity>(
                 declaration.PreprocessedEntities);
             OriginalPtr = declaration.OriginalPtr;
+            LineNumber = declaration.LineNumber;
         }
 
         public override string ToString()

src/AST/Function.cs

@@ -127,6 +127,7 @@ namespace CppSharp.AST
             OriginalFunction = function.OriginalFunction;
             Mangled = function.Mangled;
             Index = function.Index;
+            Signature = function.Signature;
             if (function.SpecializationInfo != null)
             {
                 SpecializationInfo = new FunctionTemplateSpecialization(function.SpecializationInfo);