Grub2 as optional bootloader

There have been a number of specs and bugs over the past few cycles related to bootloading, and at each phase we have considered migrating from grub 1 to grub 2 as the default bootloader in Ubuntu but ruled out this option due to concerns about the maturity of grub 2. Informal feedback at this point suggests it may now be feasible to change to this as the default for jaunty, which would get us the feedback we need to make further improvements and also give us the opportunity to sort out any remaining issues in time for the next LTS. Discuss targeting this for jaunty, and if not, discuss when we should reconsider making the switch.