Make "docker insert" errors obvious

Closes #1130
See also #1942
Add ImageInsert tests
Update release script with proper support for non-*.docker.io bucket URLs
Update release script to move https://get.docker.io/ubuntu/info to https://get.docker.io/ubuntu/ and provide a backwards-compatibility redirect (same for /builds/info)
prevent deletion if image is used by a running container
Fix the display of get.docker.io in Firefox by making our index files text/plain
Edits after code review

Return long image ID
Return streamformatted error or "raw" error
Make sure docker kill exit with failure in case of error
Just return the id; nothing else.
use utils.ParseRepositoryTag instead of strings.split in docker images
add wait, stop, start, restart, rm, rmi
on docker start, do not cleanup if already running
Merge branch 'tests/insert' of https://github.com/mrallen1/docker into mrallen1-tests/insert

Conflicts:
	server.go
Add clarification of multiple "go test" calls in hack/make/*test
Merge pull request #2669 from tianon/clarify-test-calls

Add clarification of multiple "go test" calls in hack/make/*test
Merge pull request #2657 from dotcloud/fix_docker_images_output

use utils.ParseRepositoryTag instead of strings.split in docker images
Merge pull request #2614 from dotcloud/prevent_delete_image_running_container

Runtime: prevent deletion if image is used by a running container
Merge pull request #2662 from dotcloud/do_not_cleanup_start_if_running

on docker start, do not cleanup if already running
Merge pull request #2663 from viirya/fix_nameserver_regex

Fix nameserver regex
Merge pull request #2648 from dotcloud/docker_kill_exit_code

Make sure docker kill exit with failure in case of error