Fix update-demo to work correctly with a web browser.

The built in go http.Fileserver handles If-Modified-Since in the
header by comparing it with the last modified date on the
file/directory. Since the file is unaltered when we switch to a
new container, that results in 304s when trying to fetch data.json, so
the browser doesn't fetch the new picture after doing a rolling update.

Separate issue, the Dockerfile ADD command was being interpreted as
`copy html/data.json into a directory called 'html/kitten.jpg '`,
instead of the `copy these 2 files into root`. Changed to separate
commands using COPY, per recommended dockerfile practices.
MountPath in VolumeMount is a required field. Removing the omitempty for
json/yaml.

Removed omitempty for mountpath
remove SSLv3 support in nginx config
Update guestbook,walkthrough examples to use kubectl instead of kubecfg.
Return an error if a user attempts to create an externalized UDP balancer.
Improve the pd e2e test by deleting the pod, and verifying that the PD was unmounted by
recreating the pod.
fixed resources field
Merge pull request #2851 from jlowdermilk/examples

Update guestbook,walkthrough examples to use kubectl instead of kubecfg.
Merge pull request #2850 from jbeda/nginx-ssl

remove SSLv3 support in nginx config
Merge pull request #2845 from brendandburns/proxy

Return an error if a user attempts to create an externalized UDP balancer
Merge pull request #2832 from jlowdermilk/update-demo

Fix update-demo to work correctly with a web browser.
Use util.Time consistently in types.go
Merge pull request #2820 from ravigadde/master

MountPath in VolumeMount is a required field. Removing the omitempty.
Merge pull request #2854 from brendandburns/e2e

Improve the pd e2e test
Merge pull request #2859 from mikedanese/node-doc

Fixed node.md doc
Merge pull request #2833 from liggitt/util_time

Use util.Time consistently in types.go
refactor scheduler factory to use plugin architecture style like credentialprovider and cloudprovider for configuring priority functions and fit predicates.
fixup: use string set