Remove etcd dependency from controller manager.
Add cache package.
Add ID to JSONBaseInterface
finish testing client/cache
proxy: cleanup and minor refactoring

This change includes minor refactoring and cleanup of the proxy
package including the following items:

 * Rename source files with misspelling of round robin
 * Remove unnecessary and redundant comments
 * Update comments for clarity
 * Add locking when updating the round-robin index
 * Improve method receiver names
 * Rename the LoadBalance method to NextEndpoint to add clarity

No changes in behaviour have been introduced.
Pull golang from golang
Merge pull request #792 from derekwaynecarr/update_golang_src

Pull golang from golang to fix error where hash does not match in salt state
Don't hard code load balancer zone.
Don't use zone for regional load balancers.
Revert "Revert "Use atomic create in EtcdHelper.AtomicUpdate""

This reverts commit 73b64aa490e6ae4cc9f5c0026e0d6f8bf03bbdf5.
Remove duplicated def of IsEtcdNodeExist
Merge pull request #758 from lavalamp/clientCache

Watch based client cache
Merge pull request #754 from kelseyhightower/proxy-cleanup

proxy: cleanup and minor refactoring
Merge pull request #757 from lavalamp/repCtl

Remove etcd dep from controller manager
Merge pull request #765 from brendandburns/service

Add support for regions, and use them for cloud load balancing.
Merge pull request #794 from nyaxt/reland_atomicetcd

Remove duplicated defs and reland #694.
Merge pull request #759 from brendandburns/valid

Add c-identifier validation to service ids.
Avoid data race in Proxier.OnUpdate

The bug was that the proxier is passed as value on method decleration.
This caused a copy of Proxier to be created when the method was invoked.
The copy being a shallow copy turned out to have them both reference
a same map instance, but their mutexes were different instances.
This turned out to use different mutexes before operating on a same map
instance, which didn't make sense.
Merge pull request #796 from nyaxt/fixrace

Avoid data race in Proxier.OnUpdate
Evolve the api.Status object with Reason/Details

Contains breaking API change on api.Status#Details (type change)

Turn Details from string -> StatusDetails - a general
bucket for keyed error behavior.  Define an open enumeration
ReasonType exposed as Reason on the status object to provide
machine readable subcategorization beyond HTTP Status Code. Define
a human readable field Message which is common convention (previously
this was joined into Details).

Precedence order: HTTP Status Code, Reason, Details. apiserver would
impose restraints on the ReasonTypes defined by the main apiobject,
and ensure their use is consistent.

There are four long term scenarios this change supports:

1. Allow a client access to a machine readable field that can be
   easily switched on for improving or translating the generic
   server Message.

2. Return a 404 when a composite operation on multiple resources
   fails with enough data so that a client can distinguish which
   item does not exist.  E.g. resource Parent and resource Child,
   POST /parents/1/children to create a new Child, but /parents/1
   is deleted.  POST returns 404, ReasonTypeNotFound, and
   Details.ID = "1", Details.Kind = "parent"

3. Allow a client to receive validation data that is keyed by
   attribute for building user facing UIs around field submission.
   Validation is usually expressed as map[string][]string, but
   that type is less appropriate for many other uses.

4. Allow specific API errors to return more granular failure status
   for specific operations.  An example might be a minion proxy,
   where the operation that failed may be both proxying OR the
   minion itself.  In this case a reason may be defined "proxy_failed"
   corresponding to 502, where the Details field may be extended
   to contain a nested error object.

At this time only ID and Kind are exposed