Verify first that map exist in custom emoticon before opening it

[patrick.dessalle]

Hello,

The map file in the custom emoticon does not exist by default. Instead of trying to open it and throwing an exception if it does not exist, I suggest to try if the file exist first (using os.path.exists) and then trying to open it.

I've also slightly changed the code to generate the path to the map file only once in the function and to create the empty dict self.list outside of the try/except and not twice (once in the try, once in the except).

[patrick.dessalle]

modification to check that the map file exists before opening it.

[dx]

applied