Fix the potential for loops in linked nicks. Pass along the 'trusted' bit from the...

Fix the potential for loops in linked nicks. Pass along the 'trusted' bit from the IRC module, where appropriate. Utilize it to reject access to commands requiring authentication if the nick cannot be trusted. Additionally, add a 'high security' mode where all use must originate from identified users.

git-svn-id: https://www.cernu.us/~pdbogen/svn/destult2@95 088b83a4-0077-4247-935c-42ec02c2848b