looks good, except for the comment nits

add a reorg test
The transaction is put back in the mempool so it should be available for request

move the comment inside the else if scope and rephrase it accordingly. Remove blank line

lint: sort imports

consistency: used named params only when the text argument is omitted. When we copy selected text from a QTextEdit we don't want to pass a confusing text="" param

I seearched for setShortcut and QKeySequence and found no other occurence of the + operator being used (except for the string constructor which still works, QKeySequence("Shift+Ctrl+P"))

remove commented dead code

mention the SatoshiLabs copyright and LGPL3 license in COPYING

don't forget AlignRight

• rebase on the recent stack of small refactorings that help disentangle a bit more the main_window and it's child widgets
• revert most changes in invoice_list.py: we can decouple this module in another diff, for now we still need to access the main_window for some things
• don't access send_tab from invoice_list, because invoice_list is a subwidget of the tab. Add signals and let the Send tab connect to the signal
• fix a bunch of lines that were broken by this refactor (self.* -> self.send_tab.*...) and test them (payment requests, contacts...)

Note that I needed a small patch to test this to bypass a SSL cert expiration check, as this bip70 server does currently not have a fresh certificate.

rebase, move a few methods that access history_list back to main_window so that the SendTab does not need to know the history_list API

remove unused docstring

don't add unused args to update_status and update_tabs, use lambda function to ignore argument in the signal connection

actually this does not completely address the feedback on the send_tab being accessed from history_list