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
Revisit identifiers spec
Simplify pod namespaces
Make pods a case study in identifiers.md
Document auto-set names
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
Add vagrant user to docker group
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
Add new dependencies for AWS support

- goamz: for interacting with AWS API
- gcfg: for cloud provider config file (as suggested in issue)
Initial impl. of cloud provider interface for AWS
Proposed ContainerStatus for each individual Container in a Pod.