WIP on adding nexus configuration
remove some unneeded code
add logic for handling from nexus in artifact_file
Fully support a customizable Nexus Connection

Fix authenticated Nexus downloads
Add new attribute to deploy and file resources
Refactor Nexus related library methods into its own class
Refactor Nexus remote creation to new class
use nexus_cli 4.0.0 and new syntax
Merge branch 'master' into nexus_configurations

Conflicts:
	libraries/chef_artifact.rb
update readme with new options
fix anonymous access
fix latest path and improve docs
Merge pull request #89 from RiotGames/nexus_configurations

Support Customizable Nexus Configurations