flag in the nodes table when a user changes his info. Two routines,
one to do it by type (as for widearea nodes) and another to do it by
project (as for local) nodes. This last is kinda inefficient, but
probably not too big a deal.

mkacct: Two changes.
1. Use the above changes in libdb when a user changes his info. With
   this change, no longer need to do an account update in the
   experiment page for the ron/wa nodes. The nodes are marked as
   needing the update in mkacct, based on the nodes the user has
   access to. Note, this change applies only to widearea nodes; still
   need to use the update option in the experiment menu for local
   nodes, although I plan to change that to at some point by adding a
   watchdog on the local nodes.

2. ssh2 key support. The DB can now store both ssh1 and ssh2 keys,
   however those keys are handled differently when creating the auth
   keys files for users. There are actually two files created now, the
   second being the ssh2 key file call authorized_keys2. This change
   is mirrored in the client side code as well.