#17 Option to set public permissions on new AMIs

[Jason Fulghum]

The Bundle Dialog could offer users a few common choices on permissions for new AMIs. A simple checkbox to automatically make the new AMI public after it's been registered would be a nice feature.

This involves:
- adding a new checkbox on the BundleDialog UI
- checking the state of that option to see if an additional EC2 call needs to be made at the end of BundleJob to set public permissions for the new AMI