Grammar fixes in "User Privileges" tab of User Properties

These are mostly picky cosmetic issues, but that's a good sign.

1) First, when you select a user in "Users and Groups" and select Properties, the title of the window should read "Properties" instead of "Settings"

2) The P in "Privileges" should be capitalized on the tab title.

3) "Enable access to external storage devices automatically" should just read "Access external storage devices automatically"

4) "Executing system administration tasks" should read "Execute system administration tasks"

5) "Setup printers" should read "Manage printers"

6) "Use modems" is a checkbox as is "Use serial devices such as Modems and Palm Pilots." Kinda confusing.