Only enter raw mode as needed (calling Readline()), program will receive signal(e.g. Ctrl+C) if not interact with readline.
Bugs fixed for PrefixCompleter
Press Ctrl+D in empty line will cause io.EOF in error, Press Ctrl+C in anytime will cause ErrInterrupt instead of io.EOF, this will privodes a shell-like user experience.
Customable Interrupt/EOF prompt in Config
#17 Change atomic package to use 32bit function to let it runnable on arm 32bit devices
Provides a new password user experience(readline.ReadPasswordEx()).
