Add links to tickets in ember-cli README

>There are a number of caveats you should know

I'd like to track the progress of `ember-cli` integration. The `ember-cli` README identified work needed to get to 1.0, but I've had difficulty locating tickets to keep track of the work.

Are there tickets for all the work identified in the README? Can they be added?

Start with the ember-cli README and review the work listed as needed for 1.0. Search the repository's issue history for a ticket corresponding to each item and add the relevant links; done means every identified work item has a trackable ticket or is clearly marked as lacking one.

Written by the indexing model from the issue text.