update release checklist
Add a few more small RELEASE-CHECKLIST tweaks, fixes, and improvements
there appears to be a slash prepended to a container name internally - don't tell the user about it in an error message, it might cause them to worry about it
tell anyone that might want to ignore their editor choice's backup files that there is a better way - thanks @pnasrat
Allow multiple clients to pull the same tag simultaneously

If two clients simultaneously try to pull the same tag, there was a race
whereby one would succeed and the second would generate an error. Now,
the second simply waits for the first to complete.
Handle the case where poolAdd() gives an error for an unknown pool type
Merge pull request #2910 from codeaholics/wait-for-simultaneous-pull

Allow multiple clients to pull the same tag simultaneously
Merge pull request #2904 from SvenDowideit/dont-show-user-internal-slash-in-error-message

there appears to be a slash prepended to a container name internally
Merge pull request #2814 from dotcloud/release_checklist_update

update release checklist
Merge pull request #2831 from SvenDowideit/please-ignore-squiggle-backup-files

Please ignore squiggle backup files