Add Developer Certificate of Origin Text

We purposely chose to license Docker under the Apache 2.0 license. This is a well-known
license, which is popular for its permissive and flexible properties, while still
encouraging a collaborative community. It also makes certain representations with regard
to contributions, and the rights given to contributors, the project, people who use Docker,
people who modify Docker, etc.

This approach to contributions is inspired by the popular Linux Developer
"Certificate of Origin". This approach makes it simple for new contributors to get started,
and avoids bureaucracy in tracking contributions and contributors.

To indicate accordance, each individual contribution to the Project is signed off by the
developer, using his or her real name, email address, and github handle in the format below:

	Docker-DCO-1.0-Signed-off-by: Joe Smith <joe.smith@email.com>
Merged with master
Return meaningful error for meaningless Dockerfiles
fix progressbar in docker push
 Installation for FrugalWare
+ added missing link in index.rst
* some gramatic and spelling fixes

Thx jamtur :)
add REMOTE_TODO
small batch of edits/corrections to comments
Fix typo in devmapper error message
Document "name" query parameter for "POST /containers/create" in Remote API v1.8
Merge pull request #3348 from manuel-woelker/document-name-param-in-remote-api

Document "name" query parameter for "POST /containers/create" in Remote API v1.8
Merge pull request #3347 from smarterclayton/patch-1

Fix typo in devmapper error message
Merge pull request #3343 from bwiklund/comment-edits

small batch of edits/corrections to comments
Remove old debug from tarsum
Make sure the cache lookup returns always the same result
Log files name along with their checksum in TarSum + add a Method to retrieve the checksum map
Change BuildFile in order to use TarSum instead of custom checksum
Hash the sums for directory (ureadable when there is too many
Exit with code 1 in case of error for `docker build`
Apply automatically to files named 'Dockerfile'