fix logmessage if data directory doesn't exist
changed name for ethutil hex functions
new command line options
- keyring: keyring/session identifier used by key manager
- keystore: choice of db/file key storage
- import message updated
- export: name of directory to export keys to (was bool)
main loop uses new flags and common methods in util: db, keymanager set up
remove keys file, now subsumed under ethcrypto/key_manager
added utility functions to set up db, keymanager, ethereum init and simplify key tasks