Merge pull request #168 from NiteshKant/2.x

(WIP) Introducing the concept of EurekaService and ServiceChannel.
Better avro codec error handling.
Move remaining common test classes to eureka-test-utils.
Update build system files - extract common parts.
EurekaServer stub.
Joined refactoring related to the new channel abstraction and
transport layer.
Shift back Karyon version to the latest release so we can merge this code
into the main repo.
Some Karyon code was commented out. We will be able to uncomment it when
the new Karyon version is released.
Merge pull request #170 from tbak/2.x

Eureka 2.x multiple commits