laying the groundwork for dynamic router lists

laying the groundwork for dynamic router lists

revamped the router reading section

reference counting for crypto pk env's (so we can dup them)

we now read and write pem pk keys from string rather than from FILE*,
  in anticipation of fetching directories over a socket
  (so now on startup we slurp in the whole file, then parse it as a string)

fixed a bug in the proxy side, where you could get some circuits
  wedged if they showed up while the connection was being made

svn:r110