This commit squashes all the changes in the Qt5 branch
relative to master.
Backward compatibility with Qt4 is retained.
Original authors:
- Philip Kaufmann <phil.kaufmann@t-online.de>
- Jonas Schnelli <jonas.schnelli@include7.ch>
- the send coins context menu entry was not working anymore, because
a non current version of #2220 was merged onto current master
- also removes some unneeded spaces and adds a comment to
WalletModel::getNumTransactions()