Docker Engine 1.8.0-rc1

Hello all,

Docker Engine 1.8.0-rc1 is available for testing! See the installation instructions on the bump pull request, keeping in mind that we recently introduced awesome new apt & yum repos.
Target release date is Tuesday, August 4th.
Happy testing!
## 1.8.0

### Distribution

+ Trusted pull, push and build (disabled by default)
* Make tar layers deterministic between registries
* Don't allow deleting the image of running containers
* Check if a tag name to load is a valid digest
* Allow one character repository names
* Add a more accurate error description for invalid tag name
* Make build cache ignore mtime

### Cli

+ Add support for DOCKER_CONFIG/--config to specify config file dir
+ Add --type flag  for docker inspect command
+ Add formatting options to `docker ps` with `--format`
+ Replace `docker -d` with new subcommand `docker daemon`
* Zsh completion updates and improvements
* Add some missing events to bash completion
* Support daemon urls with base paths in `docker -H`
* Validate status= filter to docker ps
* Display when a container is in --net=host in docker ps
* Extend docker inspect to export image metadata related to graph driver
* Restore --default-gateway{,-v6} daemon options
* Add missing unpublished ports in docker ps
* Allow duration strings in `docker events` as --since/--until
* Expose more mounts information in `docker inspect`

### Runtime

+ Add new Fluentd logging driver
+ Allow `docker import` to load from local files
+ Add logging driver for GELF via UDP
+ Allow to copy files from host to containers with `docker cp`
+ Promote volume drivers from experimental to master
+ Add rollover log driver, and --log-driver-opts flag
+ Add memory swappiness tuning options
* Remove cgroup read-only flag when privileged
* Make /proc, /sys, & /dev readonly for readonly containers
* Add cgroup bind mount by default
* Overlay: Export metadata for container and image in `docker inspect`
* Devicemapper: external device activation
* Devicemapper: Compare uuid of base device on startup
* Remove RC4 from the list of registry cipher suites
* Add syslog-facility option
* LXC execdriver compatibility with recent LXC versions

### Plugins

* Separate plugin sockets and specs locations
* Allow TLS connections to plugins