Add visitor class

* Request visitor identifier from data collection server.
Merge branch 'master' into add_client_service
Merge master into client service

* Add client sevice.
* bump gem version up.
* Change travis ruby version to 2.0.0, 2.1.0 is not supported.
Refactor visitor service spec

* tweaked test descriptions, changed multiline let blocks from {} to do-end
* bumped to version 0.0.3
Increase version
Merge branch 'master' into add_client_service

Conflicts:
	lib/webtrends.rb
	lib/webtrends/version.rb
Merge pull request #2 from amaabca/add_client_service

Add client service