fixed a problem in the KeyNanny client class

an instance of the KeyNanny client class was keeping the KeyNanny socket
open and connected, however the server shuts down the socket once it
reaches timeout. this has been fixed by reopening the socket in the high
level client class.
moved high level client methods from KeyNanny::Protocol to KeyNanny
add statistics about certificate use for --check option
implemented --rekey option to force re-encryption of entries
with the latest configured certificate
version bump to 1.2