Make change address for imported keys the same

Fixes #769
Update itbit/coindesk exchange rate api

itbit/coindesk exchange rate requires separate API calls per currency
Moved the calls to when the exchange rate plugin updates and when the
user modifies a selection instead of every time the program needs to
query the current exchange rate

This fixes an issue with slow response time in the send tab with the
exchange rate plugin turned on and set to coindesk or itbit
Merge pull request #820 from wozz/exch_update

Update itbit/coindesk exchange rate api
revert commit 3863ee
Multiline Address error on do_send()
Merge branch 'fixmultiline' of github.com:dabura667/electrum into dabura667-fixmultiline
separate get_errors instead of raising an exception
Merge branch 'dabura667-fixmultiline'
Merge pull request #772 from dabura667/fiximportchange

Make change address for imported keys the same
Update plugin modules in setup.py
Merge pull request #822 from mmilata/master

Update plugin modules in setup.py
Show OP_RETURN in tx dialogue
Merge pull request #824 from dabura667/txdiagopret

Show op_return in tx dialogue
Merge remote-tracking branch 'upstream/master'

Conflicts:
	gui/qt/paytoedit.py
	plugins/exchange_rate.py
	setup.py
better fees estimates
fix fee_e in settings window
fix bug #787
labels: pull in separate thread. also fix error messages
fix printing of unicode values
don't encrypt keys, because it creates new items everytime