Added Signature property to functions that provide the original function signature as accurately as possible from the original source.

src/AST/Function.cs

@@ -168,7 +168,9 @@ namespace CppSharp.AST
         public Function OriginalFunction { get; set; }
 
         public string Mangled { get; set; }
-        
+
+        public string Signature { get; set; }
+
         public override T Visit<T>(IDeclVisitor<T> visitor)
         {
             return visitor.VisitFunctionDecl(this);

src/Parser/Parser.cpp

@@ -1574,8 +1574,17 @@ void Parser::WalkFunction(clang::FunctionDecl* FD, CppSharp::AST::Function^ F,
         assert (!FTInfo.isNull());
 
         ParamStartLoc = FTInfo.getRParenLoc();
+        ResultLoc = FTInfo.getResultLoc().getLocStart();
     }
 
+    clang::SourceRange Range(FD->getLocStart(), ParamStartLoc);
+    if (ResultLoc.isValid())
+        Range.setBegin(ResultLoc);
+
+    std::string Sig;
+    if (GetDeclText(Range, Sig))
+        F->Signature = clix::marshalString<clix::E_UTF8>(Sig);
+
     for(auto it = FD->param_begin(); it != FD->param_end(); ++it)
     {
         ParmVarDecl* VD = (*it);