#145 Prevent users seeing users drop down

[Kevin Campbell]

The user drop down allows you to select to view other
user's tickets. This has two issues:

a) It doesn't make much sense when working only with
queues. Most people's workflows will not require
viewing other users' tickets.

b) It may be worth considering this in the security
framework, to prevent users from accessing other users'
tickets.

This may either be a display setting, or a security
setting, depending on how the security development goes.