Added additional mode which allows to scan barcodes without start/end key.

 Added the ability to always listen to input and turn this mode on andn off. This allows to look for scancodes without start and stop keys. The buffered code is send to the server when an "Enter" or stopKey is detected. From non-char keys only "Enter" is remapped now, because remapping the other keys introduced various problems and basically disabled all browser functions like, for example, F5.

Also added the ability to skip the Enter directly after a barcode which is added by most (all?) scanners after a barcode is scanned.