Add the ability to share a user's default list with everyone.
Merge pull request #42 from jordandukart/7.x-default-sharing

Add the ability to share a user's default list with everyone.
Better checking to see if a user exists.
Use filter_xss instead of check_plain.
Merge pull request #43 from jordandukart/7.x-fake-user

Better checking to see if a user exists.