return error status for payment requests
WaitingDialog class for better encapsulation
show request memo
hide help buttons if a payment request is shown
add paymentrequest to setup.py
multi seed and mpk dialogs
wallet.is_used() method
mpk hex encoding
Merge remote-tracking branch 'upstream/master'

Conflicts:
	gui/qt/main_window.py
	setup.py
Merge branch 'master' of https://github.com/pooler/electrum-ltc into electrum-myr

Conflicts:
	gui/qt/main_window.py
	setup.py