[AESH-109]
added CompletionRegistration thats returned when you add a Completion object
to Console.
[AESH-111]
option completion should also work with shortnames
arguments are better parsed and offset should work
[AESH-111]
changed Command, removed InjectConsole and added .addCommand(Command)
[AESH-110]
removed old toString and renamed getAsString to toString so it should work
better with PrintWriter
[AESH-111]
added CommandResult
implemented AeshConsole.removeClass
++ fixes