Added support for python virtualenv plugin

Change-Id: Ie21699d43ff6331ae93cc83d8f9751ac683b43fa
Added support for Delivery Pipeline Plugin

Change-Id: I54cfa9153700e141d8ba78c881998553b8081658
ArtifactDeployer Plugin support added

This plugin makes it possible to copy artifacts to remote locations.

Change-Id: I39fbee7b397efb8560f340f0f02b51bf6ebcfd74
Merge "Added support for Delivery Pipeline Plugin"
Merge "Added support for python virtualenv plugin"