+o have a config file (or section in radiusd.conf) that tells rlm_sql
+ what the names of the tables and columns are instead of hardcoding
+ them
+o split rlm_files into rlm_users, rlm_fastusers (in-memory hash),
+ rlm_detail, they all should share as much code as
+ possible though, not be big cut-and-paste jobs
+o fix the request list walking code, to scan each element no more than
+ once per second.