single key shortcuts get triggered in tags control of relation editor

[flaimo]

1) in response to ​http://josm.openstreetmap.de/ticket/6472 remap the "r" key to the "paste tags" function
2) select some element and press cmd+c to copy it (and therefor it's tags)
3) click the create new relation button
4) in the tags control select the first cell and start typing something with "r"

wrong behavior: as soon as you hit the "r" key, all the tags get pasted into the key control.

when typing actual text in text controls, single key shortcuts should never get triggered.

version: 4201 (also 4064)

[akks]

In 6024/josm:

fix #6546: disable single key and shift- shortcuts in relation editor
+ add @Override annotations