Add netlink hooks to delete a bridge dev

Signed-off-by: Dhammika Pathirana <dhammika@gmail.com>

Docker-DCO-1.1-Signed-off-by: Dhammika Pathirana <dhammika@gmail.com> (github: dhammika)
Add code review updates

Docker-DCO-1.1-Signed-off-by: Dhammika Pathirana <dhammika@gmail.com> (github: dhammika)
Reopening stdin, stdout and stderr if they are pointing to /dev/null to not have '/dev/null' from the global namespace opened inside the container.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Add more Travis matrix targets (being explicit about CGO)

I've also updated the comments with the current status of the commented-out targets (since we're getting close to having them available for our Travis-use in the relevant upstreams).

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Merge pull request #113 from tianon/travis-cgo

Add more Travis matrix targets (being explicit about CGO)
Merge pull request #46 from dhammika/44-delete-bridge

Add netlink hooks to delete a bridge dev #44
Merge pull request #107 from vishh/dev_null

Reopening stdin, stdout and stderr if they are pointing to /dev/null.
Small fix for GetAllCgroups().

Incorrect parsing of length of fields.

Docker-DCO-1.1-Signed-off-by: Victor Marmol <vmarmol@google.com> (github: vmarmol)
Merge pull request #114 from vmarmol/cgroups

Small fix for GetAllCgroups().
Add "linux/arm" to Travis

Docker-DCO-1.1-Signed-off-by: Andrew Page <admwiggin@gmail.com> (github: tianon)
Merge pull request #115 from tianon/travis-arm

Add "linux/arm" to Travis
Adding RunIn to run a user specified command in an existing container, wait for it to exit and return the exit code.
RunIn will connect to a user specified Terminal before running the command.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Updated RunIn API to match the new console handling behavior in HEAD.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
'nsinit exec' now uses namespaces.RunIn instead of namespaces.ExecIn.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Fix runin code for nsinit
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Merge pull request #64 from vishh/runin

Adding RunIn to run a user specified command in an existing container.
Update dockerfile for running tests
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Add makefile with build and test targets
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Add start of netlink unit tests
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)
Add code coverage to the tests
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@docker.com> (github: crosbymichael)