Reduce verbosity when Options.Quiet is set.

src/Generator.Tests/GeneratorTest.cs

@@ -42,7 +42,6 @@ namespace CppSharp.Utils
             testModule.LibraryDirs.Add(options.OutputDir);
             testModule.Libraries.Add($"{name}.Native");
 
-            Diagnostics.Message("Looking for tests in: {0}", path);
             var files = Directory.EnumerateFiles(path, "*.h", SearchOption.AllDirectories);
             foreach (var file in files)
             {

src/Generator/Driver.cs

@@ -112,7 +112,8 @@ namespace CppSharp
             switch (result.Kind)
             {
                 case ParserResultKind.Success:
-                    Diagnostics.Message("Parsed '{0}'", string.Join(", ", files));
+                    if (!Options.Quiet)
+                        Diagnostics.Message("Parsed '{0}'", string.Join(", ", files));
                     break;
                 case ParserResultKind.Error:
                     Diagnostics.Error("Error parsing '{0}'", string.Join(", ", files));
@@ -346,7 +347,8 @@ namespace CppSharp
 
                     output.TranslationUnit.Module?.CodeFiles.Add(file);
 
-                    Diagnostics.Message("Generated '{0}'", fileRelativePath);
+                    if (!Options.Quiet)
+                        Diagnostics.Message("Generated '{0}'", fileRelativePath);
                 }
             }
         }

src/Generator/Passes/CheckAmbiguousFunctions.cs

@@ -62,7 +62,7 @@ namespace CppSharp.Passes
             }
 
             if (function.IsAmbiguous)
-                Diagnostics.Message($"Found ambiguous overload: {function.QualifiedOriginalName}");
+                Diagnostics.Debug($"Found ambiguous overload: {function.QualifiedOriginalName}");
 
             return true;
         }