Missing icon on Linux

[adrienjoly]

(cf https://github.com/openwhyd/openwhyd-electron/issues/21#issuecomment-416074234)

[adrienjoly]

things to try:

• https://stackoverflow.com/questions/50363595/electron-linux-app-is-not-displaying-the-icon-after-built
• https://stackoverflow.com/questions/31529772/how-to-set-app-icon-for-electron-atom-shell-app
• https://github.com/onmyway133/blog/issues/66
• https://github.com/openwhyd/openwhyd-electron/issues/21#issuecomment-416076967
• https://github.com/onmyway133/IconGenerator