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.

gui/qt/paytoedit.py

@@ -18,7 +18,7 @@
 
 from PyQt4.QtCore import *
 from PyQt4.QtGui import *
-from qrtextedit import QRTextEdit
+from qrtextedit import ScanQRTextEdit
 
 import re
 from decimal import Decimal
@@ -30,11 +30,9 @@ RE_ALIAS = '(.*?)\s*\<([1-9A-HJ-NP-Za-km-z]{26,})\>'
 frozen_style = "QWidget { background-color:none; border:none;}"
 normal_style = "QPlainTextEdit { }"
 
-class PayToEdit(QRTextEdit):
-
+class PayToEdit(ScanQRTextEdit):
     def __init__(self, win):
-        QRTextEdit.__init__(self)
-        self.win = win
+        super(PayToEdit,self).__init__(win=win)
         self.amount_edit = win.amount_e
         self.document().contentsChanged.connect(self.update_size)
         self.heightMin = 0
@@ -235,3 +233,10 @@ class PayToEdit(QRTextEdit):
         cr = self.cursorRect()
         cr.setWidth(self.c.popup().sizeHintForColumn(0) + self.c.popup().verticalScrollBar().sizeHint().width())
         self.c.complete(cr)
+
+
+    def qr_input(self):
+        data = super(PayToEdit,self).qr_input()
+        if data.startswith("bitcoin:"):
+            self.scan_f(data)
+            # TODO: update fee