implement "-c" option to allocate a number of CPU shares to a container
if -c is not specified, do not set cpu.shares (instead of using the default value of 1024)
in the tests, use a non-default value for cpu.shares
propagate CpuShares in mergeConfig
refactor api.go
Major rearrange of the documentation.
add writeJson
Updated commands index to show better title.
Small syntax fix in couchDB
Merge branch 'master' of github.com:dotcloud/docker into 471-cpu-limit
Expand upon Builder documentation and tidy

Standardizes on uppercase for instructions, gives 
example usage.
Wrap at 80 columns
refactor api.go
add writeJson
Update api_test.go to reflect new api.go
Merge branch 'refactor_api_file' of github.com:dotcloud/docker into refactor_api_file
Merge pull request #582 from dotcloud/refactor_api_file

* Api: refactor api.go file to ease the streaming
Made AWS region and ami to be configurable through the ENV variables.
Make examples bash-highlighted
Remove DOCKER-VERSION, easier to maintain
Add example of multiple FROM steps
Merge pull request #584 from boffbowsh/builder-documentation

* Documentation: Updated Docker builder docs to clean up format and add new information and examples
Fixes the README build example to make it work
Added install instructions for RackSpace cloud using Ubuntu 12.04, 12.10, 13.04