Added a mechanism for determining if the program is being run with admin privileges.
Added UI to support the "All users" vs "Just this user" distinction.
IInstallVerifiers now return arrays of IStatus, which allows GeneralInstallVerifier to alert on multiple failures at once.
Shortcuts are now created per-user or per-system.
Fixed a bug in selecting "All Users" or "Just this user" - user choice wasn't updating error checks.
PathAction and EnvironmentAction now respect this user vs all users.