Trace logging project

[ghudson@MIT.EDU]

Based on recent feedback from krb5 users, I've written up an early
project page on trace logging:

  http://k5wiki.kerberos.org/wiki/Projects/Trace_logging

I'm currently at the rough design stage, and am interested in feedback
on:

  * How trace logging information should be selected, particularly
    from people who have used trace logging facilities in other
    projects.

  * Whether it's better for tracing calls to require a krb5 context
    for better isolation and thread safety, or not to require a
    context for better code penetration.

There's a bit more on both bullet points in the project page.