Added a lot of basic instructions on various topics
Redundant message in basics.
add support for xz compression

This adds xz as a compression option.
xz is alread supported by bsdtar without the external xz program.
use xz compression when pushing images to the registry

This makes the xz compression the default.
Merge remote-tracking branch 'dotcloud/master' into dhrp/docs
Fixed a lot of language and small things.
Merge remote-tracking branch 'unclejack/194-high-image-compression'
Fix a bug which caused 'docker push' to fail with 411-lenght-required in Go 1.0
Merged dhrp/docs
Adding ip and brctl wrappers
Creating the network bridge device when docker starts up

If the docker bridge device doesn't exist yet the following occurs:

1. All interfaces are enumerated
2. Each interface address is parsed into an IP and mask
3. Any ipv6 addresses are ignored
4. If the docker bridge network range conflicts with the mask of an
   existing device then docker bombs out
5. Create the docker bridge device

Eventually we can add in intelligent network selection for the docker bridge.
Clean up network bridge if setup fails during device creation
Refactoring bridge functions to use struct methods
Simplifying networkOverlap and expanding test cases
Ran gofmt on network_test.go
Adding flags to set network bridge interface and address at runtime
Pulling bridge device into lxc template from networkManager
Refactoring CheckAddr() to return errors more cleanly
Update the ip command wrapper to return the output
Add check of overlapping routes