Add a Go-based command completion routine.
README fixups and grammar.
Merge branch 'master' of https://github.com/thejerf/readline into thejerf-master

Conflicts:
	README.md
	readline.go

Moved helper functions to readline.c;
Renamed completerShim to _go_readline_completer_shim;
Renamed completer to DefaultCompleter;
Added copyright header in readline.c;
Replaced println() with fmt.Println in example/echo.go.
Added @thejerf