libcontainer/network: add netns strategy

Docker-DCO-1.1-Signed-off-by: Johan Euphrosine <proppy@google.com> (github: proppy)
libcontainer/nsinit/init: move mount namespace after network

Docker-DCO-1.1-Signed-off-by: Johan Euphrosine <proppy@google.com> (github: proppy)
libcontainer: goimports

Docker-DCO-1.1-Signed-off-by: Johan Euphrosine <proppy@google.com> (github: proppy)
libcontainer: remove duplicate imports

Docker-DCO-1.1-Signed-off-by: Johan Euphrosine <proppy@google.com> (github: proppy)
Add initial plugin flag to pass lxc and native driver options
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Dont use custom marshaling for caps and namespaces

This also adds an enabled field to the types so that they
can be easily toggled.
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Allow caps to be toggled in native driver with plugin flag
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Add ability to work with individual namespaces
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Merge branch 'nsinit' of https://github.com/proppy/docker into proppy-nsinit

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Merge branch 'proppy-nsinit' into pluginflag

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Allow containers to join the net namespace of other conatiners
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Factor out the native driver config options
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Change flag to -o and --opt
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Change syntax to use dots
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Add more native driver options
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Change placement of readonly filesystem

We need to change it to read only at the very end so that bound,
copy dev nodes and other ops do not fail.
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Add cpuset.cpus to cgroups and native driver options
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Add unit test for lxc conf merge and native opts
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Merge branch 'master' into pluginflag

Conflicts:
	pkg/cgroups/cgroups.go
	pkg/libcontainer/nsinit/exec.go
	pkg/libcontainer/nsinit/init.go
	pkg/libcontainer/nsinit/mount.go
	runconfig/hostconfig.go
	runconfig/parse.go
	runtime/execdriver/driver.go
	runtime/execdriver/lxc/lxc_template.go
	runtime/execdriver/lxc/lxc_template_unit_test.go
	runtime/execdriver/native/default_template.go
	runtime/execdriver/native/driver.go

Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
Fix compile and unit test errors after merge
Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)