update tcpenv and lrpip calls to use -> syntax

* update tcpenv and lrpip calls to use -> syntax

* don't load plugins twice.
    Not exactly sure where that feature crept in some time ago. It was suppressed by checking to see if a queue plugin was already registered, and then bailing out on subsequent register_hook runs. I noticed it in testing, b/c I didn't have a queue plugin loaded. This removes the duplicate calls to register_hook.

* adds caching of the AUTH methods. Cache the list and avoid having to generate it on every connection.

* reduces several instances of duplicated code into new functions

* other PBP changes (early exits, less indention, fewer unnecessary parens,
  etc.)
This third 'return' will never execute if $rc == DENY_DISCONNECT or $rc == DENYSOFT_DISCONNECT