Add fs.NotifyOnOOM for out-of-memory notifications

Docker-DCO-1.1-Signed-off-by: Bernerd Schaefer <bj.schaefer@gmail.com> (github: bernerdschaefer)
Rename Container -> Config.

Docker-DCO-1.1-Signed-off-by: Victor Marmol <vmarmol@google.com> (github: vmarmol)
Merge pull request #39 from vmarmol/rename-container

Rename Container -> Config.
Fix nits on chan direction and defer

Closes #9
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Remove generic context and replace with fields
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Update sample config with context changes
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Add tests and sample files for selinux and apparmor
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Merge pull request #51 from crosbymichael/type-context

Strongly type context on the Config
Replace pid and started file with State type
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Update readme with state.json changes
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Update code based on review comments
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Rename to InitPid
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Merge pull request #48 from crosbymichael/add-oom-event

Add oom notify event
Merge pull request #50 from crosbymichael/create-state

Create state
1. Added a basic version of network stats inside network package.
2. Introducing a new checkpoint file 'network.stats' which will contain the network runtime information (veth interface names for now).
3. Adding network stats to 'nsinit stats'.
4. Added a libcontainer Stats API to get both network and cgroup stats

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Created a global runtime checkpoint for libcontainer. Got rid of the network specific runtime checkpoint.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
RuntimeCkpt is now State and the checkpoint file is called state.json.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Refactores network Interface a bit to use NetworkState struct instead of a map for passing runtime information around.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Refactoring.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Further refactoring.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)