Adding and supporting element <urls> to the configuration in pom.xml

 - Users can now have either <url> or <urls> inside their pom (They cannot have both at the same time).

 - The <url> and <urls> elements take effect during push and update goals.

 - Update goal has also been modified to support updating of memory, instances and uris.

Change-Id: Ide138e1d8f85fececbaac1c1651d943ee809f76d