Remove listeners for specific events in Task class
Remove listeners for specific events in Task class

This change is necessary for Electron 3 to a bug in Node.js 10.2.x which causes
the `removeAllListeners` method to no longer remove all listeners for any event
name when no argument is passed:

https://github.com/nodejs/node/pull/20924

This issue has been fixed in Node.js 10.3.0+ so we will have to remove this
workaround when we move to Electron 4.0 to avoid future event handler leaks.

brettle/atom,Mokolea/atom,PKRoma/atom,Mokolea/atom,brettle/atom,Mokolea/atom,PKRoma/atom,atom/atom,atom/atom,brettle/atom,PKRoma/atom,atom/atom