Help button for many warning messages; Restored warning icon.

The error icon was gone because we are now using the ErrorDialog, which didn't have it.  So added back explicitly.  I decided to go with wxART_WARNING rather than wxART_ERROR because nearly all of these present as warnings.

src/import/RawAudioGuess.cpp

@@ -209,7 +209,11 @@ static void Extract(bool bits16,
    }
 
    if( dataSizeIn < 1 )
-      throw SimpleMessageBoxException{XO("Bad data size")};
+      throw SimpleMessageBoxException{
+         XO("Bad data size. Could not import audio"),
+         XO("Warning"), 
+         "Error:_Importing_raw_audio"
+      };
 
    size_t dataSize = (size_t)dataSizeIn;