pids limit support

update bash commpletion for pids limit

update check config for kernel

add docs for pids limit

add pids stats

add stats to docker client

Signed-off-by: Jessica Frazelle <acidburn@docker.com>

docs/reference/commandline/create.md

@@ -74,6 +74,7 @@ Creates a new container.
       -P, --publish-all             Publish all exposed ports to random ports
       -p, --publish=[]              Publish a container's port(s) to the host
       --pid=""                      PID namespace to use
+      --pids-limit=-1                Tune container pids limit (set -1 for unlimited), kernel >= 4.3
       --privileged                  Give extended privileges to this container
       --read-only                   Mount the container's root filesystem as read only
       --restart="no"                Restart policy (no, on-failure[:max-retry], always, unless-stopped)

docs/reference/commandline/run.md

@@ -74,6 +74,7 @@ parent = "smn_cli"
       -P, --publish-all             Publish all exposed ports to random ports
       -p, --publish=[]              Publish a container's port(s) to the host
       --pid=""                      PID namespace to use
+      --pids-limit=-1                Tune container pids limit (set -1 for unlimited), kernel >= 4.3
       --privileged                  Give extended privileges to this container
       --read-only                   Mount the container's root filesystem as read only
       --restart="no"                Restart policy (no, on-failure[:max-retry], always, unless-stopped)