a command can now return SHELLMATTA_BUSY
This will be passed back to the caller of processData
afterwards the instance has to be called with the same parameters
The shellmatta will then just call the busy command until it finishes
as soon as the command returns != SHELLMATTA_BUSY the instance will continue processing the rest of the input data
If a command returns SHELLMATTA_CONTINUE all received data is passed to this command until it returns != SHELLMATTA_CONTINUE or a cancel is received
The data is passed stdin like and can be read byte by byte vie shellmatta_read
The stdin buffer is overwritten witch each new char
