How to Add multitask button to the Phone / Change button functions? topic

I have a nexus 4, the right most button on the nexus 4 is the multitask button, showing all the running apps.

Today i ordered an LG optimus e970 for my brother since it was on sale and i noticed that to show all running problems, i need to hold the home button and that's very annoying. The rightmost button on the optimus is just settings button.


How do i change the functions of the button and make the rightmost button the multitask button?
Can custom roms like cyangmod change it?