Adding IPv6 network support

Docker-DCO-1.1-Signed-off-by: Malte Janduda <mail@janduda.net> (github: MalteJ)
Saturate negative memory stat values at '0'.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
Merge pull request #201 from vishh/stats_rounding

Saturate negative memory stat values at '0'.
Address6 -> IPv6Address and Gateway6 -> IPv6Gateway

Docker-DCO-1.1-Signed-off-by: Malte Janduda <mail@janduda.net> (github: MalteJ)
Merge pull request #203 from MalteJ/master

Adding IPv6 network support
Fix leaking file descriptor in NetNs strategy

Docker-DCO-1.1-Signed-off-by: Hugo Duncan <hugo@hugoduncan.org> (github: hugoduncan)
Merge pull request #205 from hugoduncan/fix-leaking-fd-in-netns

Fix leaking file descriptor in NetNs strategy
Refactored SetNs funcs. Implemented ChangeName.

I've refactored NetworkSetNsPid and NetworkSetNsFd following
what we already have in place for Add/Del Ip and Add/Del Link.
I've reimplemented NetworkChangeName function which is now
using netlink for changing the interface name. I added tests too.
I've moved the original syscall implementation at the bottom
to keep it together with the other non-netlink functions.

Signed-off-by: Milos Gajdos <milosgajdos83@gmail.com> (github: milosgajdos83)
Added VLAN and MAC VLAN device support to netlink

You can now create VLAN and MAC VLAN devices using netlink.
I've also added tests for both VLAN and MAC VLAN stuff.

Signed-off-by: Milos Gajdos <milosgajdos83@gmail.com> (github: milosgajdos83)
Merge pull request #206 from milosgajdos83/vlan-macvlan

Added support for VLAN and MAC VLAN interfaces plus did a bit of refactoring.
implementing SetInterfaceMac

Docker-DCO-1.1-Signed-off-by: Malte Janduda <mail@janduda.net> (github: MalteJ)
MACAddress -> MacAddress

Docker-DCO-1.1-Signed-off-by: Malte Janduda <mail@janduda.net> (github: MalteJ)
Merge pull request #208 from MalteJ/master

Expose parameter to set interface MAC address