Refactor pipeline routed store and its factory

1. Force using pipelineRoutedStore for routedStore
2. Deprecated threadPoolBased routedStore
more refactorings on RoutedStore
fixed a bug that throws exceptions for some tests
added a test for zone affinity get
Added support for GET zoneAffinity

1. Added config options in clientConfig parser
2. Added ZoneAffinity Class
3. Added reference of ZoneAffinity Class in RoutedStoreConfig
4. Added GET ZoneAffinity support in PipelineRoutedStore
Updated zoneAffinityGet implementation after code review

1. Instantiate ZoneAffinity object inside clientConfig
2. Instantiate ZoneAffinity object in PipelineRoutedStore's
   constructor if null pointer is passed in
3. Use three zone cluster in ZoneAffinityGetTest and make client
   in each of the three zones in three test
first implementation of zone-affinity-getall
refactor zone-affinity-getall after review
added zone affinity get versions
remove toggle for using pipeline routed store or not
First pass of refactoring Coordinator Netty pipeline: using common thread pool instead of isolating
Refactoring Coordinator to use standard Netty pipeline which is more scalable than the previous FatClientWrapper design
Restructuring the Voldemort REST server and Coordinator under a common package: voldemort.rest
Changing vector clock serialization to base64 instead of json to improve performance
Revert "Changing vector clock serialization to base64 instead of json to improve performance"

This was part of performance benchmarking. It got wrong pushed to this branch.

This reverts commit fe8479365d8f1eca8f34a09817caa93ed7437dcd.
RebalanceController Scheduler + Unit Test
Add license info
Get rid of replica type from the code base

(1) Add new message to the admin protocol.
(2) Introduce a new class for rebalacing called RebalanceTaskInfo.
(3) Remove replica type from everywhere else.

Added // TODO (Sid) style comments where I wasn't sure.
Also added // TODO (Sid)  on the donor based path.
Fix tests that rely on replica type
Add special case for an empty partition list