check port is valid
fix regression in /etc/hosts
Some format and syntax changes.

* Added sudo as per convention to docker commands
* Break the Dockerfile block up
* Redis is a proper noun
* Minor whitespace fixes
A variety of syntax and style fixes for the Docker examples

* Made Docker a proper noun when needed.
* Fixed code syntax
* Fixed some whitespace issues
* Fixed some typos and grammar
* Tidied up some examples
Ensure container name on register
Add lock around write operations in graph

The graph uses a persistent database connection so
a lock is required because our current sqlite3 driver
does not implement retry logic when the ErrBusy is received.
Merge pull request #2501 from dotcloud/2480-check_port-fix

check port is valid
Merge pull request #2533 from jamtur01/add_sudo

Some format and syntax changes.
Merge pull request #2551 from dotcloud/concurrent-db-access

Add lock around write operations in graph
Merge pull request #2525 from dotcloud/fix_hostnames

Fix regression in /etc/hosts
Merge pull request #2549 from dotcloud/ensure-container-name

Ensure container name on register
Merge pull request #2534 from jamtur01/examples_fixes

A variety of syntax and style fixes for the Docker examples