Change minion to node

Contination of #1111

I tried to keep this PR down to just a simple search-n-replace to keep
things simple.  I may have gone too far in some spots but its easy to
roll those back if needed.

I avoided renaming `contrib/mesos/pkg/minion` because there's already
a `contrib/mesos/pkg/node` dir and fixing that will require a bit of work
due to a circular import chain that pops up. So I'm saving that for a
follow-on PR.

I rolled back some of this from a previous commit because it just got
to big/messy. Will follow up with additional PRs

Signed-off-by: Doug Davis <dug@us.ibm.com>

examples/runtime-constraints/README.md

@@ -79,13 +79,13 @@ $ cluster/kubectl.sh run cpuhog \
     -- md5sum /dev/urandom
 ```
 
-This will create a single pod on your minion that requests 1/10 of a CPU, but it has no limit on how much CPU it may actually consume
+This will create a single pod on your node that requests 1/10 of a CPU, but it has no limit on how much CPU it may actually consume
 on the node.
 
 To demonstrate this, if you SSH into your machine, you will see it is consuming as much CPU as possible on the node.
 
 ```
-$ vagrant ssh minion-1
+$ vagrant ssh node-1
 $ sudo docker stats $(sudo docker ps -q)
 CONTAINER           CPU %               MEM USAGE/LIMIT     MEM %               NET I/O
 6b593b1a9658        0.00%               1.425 MB/1.042 GB   0.14%               1.038 kB/738 B
@@ -150,7 +150,7 @@ $ cluster/kubectl.sh run cpuhog \
 Let's SSH into the node, and look at usage stats.
 
 ```
-$ vagrant ssh minion-1
+$ vagrant ssh node-1
 $ sudo su
 $ docker stats $(docker ps -q)
 CONTAINER           CPU %               MEM USAGE/LIMIT     MEM %               NET I/O