First shot of implementing request with metadata API.
minor change
First pass of enabling request URI built from variables and template.
Changes to implementation of withMetaData().
Updates after design changes.
Move withLoadBalancer() and withClientConfig() to ResourceGroup().
Change rxnetty version to 0.3.6. Implementation of ResourceGroup. Change to ConfigurationBasedServerList to make the server list part of client configuration.
Merge pull request #103 from allenxwang/2.x-commonclient

WIP: 2.x commonclient