disallow spaces in the receiver and sender field of the transfer coins dialog

[trendzetter]

Spaces should not be allowed

[jmininger]

We trim leading / trailing whitespace from account names when the user goes to the next step of the transfer workflow. Is this what you mean?

[trendzetter]

I managed to send to
k: 882ce1c85c9b5ffac008fe13367ed5c2936d68cbd9e16e84492e5413ad5fb827
(a valid k-account except for the excessive space after the colon)
I think there probably is a regex check possible to stop that from happening that does not harm valid transfers.