add e2fsprogs package
Format Dockerfile following best-practices

In particular, we want to run `apt-get update` and `apt-get install` on the same line to avoid caching issues.  
Also reduces the number of AUFS layers as recommended, https://docs.docker.com/articles/dockerfile_best-practices/

A few additional things might be worth considering(?):
- Why ubuntu:14.04 by default?  A Debian base, as mentioned in the article, would be considerably smaller.
- perhaps consider COPY in place of ADD

(apologies for such pedantic edits!)
Merge pull request #37 from cboettig/master

Format Dockerfile following best-practices
Merge pull request #35 from sroegner/master

add e2fsprogs package
Add an extra environment variable DOCKER_DAEMON_ARGS
Added a section to the readme about DOCKER_DAEMON_ARGS
Merge pull request #39 from tarnfeld/feature/docker-args

Add an extra environment variable DOCKER_DAEMON_ARGS
Use $DOCKER_DAEMON_ARGS when using daemon mode
Merge pull request #40 from antoinerg/master

Use $DOCKER_DAEMON_ARGS when using daemon mode
Merge pull request #1 from jpetazzo/master

Update fork with source repository