Add third_party/etcd to .gitignore

Otherwise the tree looks "dirty" after hack/install-etcd.sh is executed.

Tested:
- Ran `git status` after running `hack/install-etcd.sh`.

Signed-off-by: Filipe Brandenburger <filbranden@google.com>
Add option to enable a simple CORS implementation for the api server
Move CORS handler wrapping into cmd/apiserver and switch config flag to a list of allowed origins
Move RecoverPanics to be the top level wrapped handler.  Add new method to be sure a logger has been generated instead of assuming one has.  Move regexp list compilation into a utility and pass regexp list into CORS.
Switch LogOf from panicking when logger is missing to creating logger with the defaults.
Update CORS tests to a table-based test and cover more cases.
Rebased and fixed test cases
No DNS in vagrant cross minions, need explicit IP as host
Misc. doc updates: Go setup, ssh reqd. on GCE, etcd reqd. for local, moved community links to wiki
kubelet: move docker-related code into sub-package
Merge pull request #1279 from derekwaynecarr/ip_as_hostname_vagrant

No DNS in vagrant cross minions, need explicit IP as host
Create passthroughLogger when LogOf is called and request has no logger
Merge pull request #1133 from jwforres/enable_cors

Add option to enable a simple CORS implementation for the api server
Merge pull request #1281 from bgrant0607/master

Misc. doc updates: Go setup, ssh reqd. on GCE, etcd reqd. for local, moved community links to wiki
Proposed ContainerStatus for each individual Container in a Pod.
Fix some readme and script bugs in examples (take 2).

v2: Resolve issues from comments, fix bugs in update-demo example, rename files for clarity, add turn-down steps.

v3: Add more set commands, clean up rest of env var checks.
Merge pull request #1265 from mbforbes/master

Fix some readme and script bugs in examples (take 2).
Introduce ContainerStates. Currently keep it has the same set as PodStatus:
Waiting, Running, Termination. For each state, there are some meaningful
status associated with it.
Clean up
Fix the e2e scripts after PR 1284 which added a new file.
Merge pull request #1286 from brendandburns/fix

Fix the e2e scripts after PR 1284 which added a new file.