Add fullname to Wix::Extensions::UserPrivileges::LocalUser

[garymazz]

Please add support for a full name attribute to Wix::Extensions::UserPrivileges::LocalUser

thanks..

[dblock]

Please contribute, https://github.com/dblock/msiext/blob/master/CONTRIBUTING.md.

Note that this might not be possible since that might be coming from ActiveDirectory.

[garymazz]

great work on these extensions.. I already forked the project.. and started to look at the issue.

localuser account creation is permitted as long as user running the installer has privileges to create user accounts.

I'm also trying to fix some issues on the main wix project and the wix plugin for maven :)