allow mod authors to add their own icon

- allow mod authors to dynamically add elements to the menu
- this can include background image, DOM events, etc.

Signed-off-by: -Underdog- github.underdog@gmail.com
- remove line break at end of file

Signed-off-by: -Underdog- github.underdog@gmail.com
Merge pull request #2407 from Underdog-01/patch-11

allow mod authors to add their own menu icon