Update setup.py

plugin name added
Update main_window.py
Create plot.py
Update plot.py
Update plot.py
QR code fixes

New classes ScanQRTextEdit and ShowQRTextEdit.
Reason: dependencies on zbar availability and issues with the QRTextEdit constructor.
- ScanQRTextEdit needs access to the config (fetch camera). It needs to load
the zbar processor properly before trying to scan. Keeping a reference to
the processor in qrscaner fixes the crashes on windows.
- ShowQRTextEdit should not have access to scan_qr().
- no need to setReadOnly anymore. It is clear from the class name.

Show master pub keys now has a Combobox if multiple accounts are
available.
Merge pull request #899 from Tafelpoot/qrcode_fix2

QR code fixes
init qrscanner processor in scan_qr
remove 'select account' label
fix #895
fix is_watching_only for imported wallets
add window title for show_private_key and show_public_key
optimized deserialize and modified assert for multisig
corrected deserialize
Merge pull request #906 from Tafelpoot/tx_optimize

optimized deserialize and modified assert for multisig
made some statements more pythonic and optimized a bit
Merge branch 'master' of https://github.com/spesmilo/electrum into official
separate signtxwithkey and signtxwithwallet, and simplify sign_transaction
signtxwithkey: use prompt if privkey is not passed
add account info for internal transfer description