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
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