add ability to show a receiving address on ledger screen

[mzhou]

No description provided.

[coveralls]

Coverage decreased (-0.005%) to 42.927% when pulling 8d2e990 on mzhou:ledger_confirm_address into 3851e78 on spesmilo:master.

[SomberNight]

Tested, and works :)

However, there is equivalent functionality for Trezor (and KeepKey and Digital Bitbox), implemented differently. I think it would be better if this PR was made to be similar to that.

electrum/gui/qt/address_list.py

Line 163 in 3851e78

run_hook('receive_menu', menu, addrs, self.wallet)

electrum/plugins/trezor/qt_generic.py

Lines 189 to 197 in 3851e78

	@hook
	def receive_menu(self, menu, addrs, wallet):
	if type(wallet) is not Standard_Wallet:
	return
	keystore = wallet.get_keystore()
	if type(keystore) == self.keystore_class and len(addrs) == 1:
	def show_address():
	keystore.thread.add(partial(self.show_address, wallet, addrs[0]))
	menu.addAction(_("Show on %s") % self.device, show_address)

[coveralls]

Coverage decreased (-0.01%) to 42.856% when pulling 4df087c on mzhou:ledger_confirm_address into 13bf539 on spesmilo:master.

[coveralls]

Coverage decreased (-0.009%) to 42.861% when pulling 4df087c on mzhou:ledger_confirm_address into 13bf539 on spesmilo:master.

[marceloneil]

Is this variable necessary?