Instance-wise configuration.

- components shall not read configuration from SystemConfig.
  instead, application shall read SystemConfig, override them with
  command-line switch and configuration file and pass them to
  component instances.
- Config.Override() function accepts more than one configuration
  object to apply.
- Following constructors accept max-vbuckets and config arugments,
  - dataport.NewServer() and dataport.NewClient()
  - projector.client.NewClient()
  - projector.NewProjector()
  - queryport.NewClient() and queryport.NewServer()
  - queryport.Application(), example application.
- fixed `indexer` to pass configuration object as constructor arugment.

Change-Id: Ic24402b5db7296c5fca0fba4aed1946c5cc4a55d
Reviewed-on: http://review.couchbase.org/43677
Reviewed-by: Pratap Chakravarthy <prataprc@couchbase.com>
Tested-by: Pratap Chakravarthy <prataprc@couchbase.com>