update QRCodeDialog

- remove unused #include <QDebug> and lblBTC label
- update Bitcoin input field to a BitcoinAmountField to allow Bitcoin unit selection
- use BitcoinUnits::format for the resulting amount parameter in the generated URI (always use BTC as per BIP21)
- move MAX_URI_LENGTH and EXPORT_IMAGE_SIZE to guiconstants.h
- add OptionsModel in AddressBookPage and use it in on_showQRCode_clicked() to pass it to QRCodeDialog
- add OptionsModel in QRCodeDialog to enable display unit updates
- add updateDisplayUnit() slot to be able to imediately update currently set bitcoin unit
- make all labels in the UI-file plain text
- resize dialog to match for an updated layout (fields are now stacked and new field)
- remove unused parameters from private slots
- only enable save button, when QR Code was generated
- show message when entered amound is invalid
- add read-only QPlainTextEdit field to output generated URI

src/qt/addressbookpage.cpp

@@ -2,6 +2,7 @@
 #include "ui_addressbookpage.h"
 
 #include "addresstablemodel.h"
+#include "optionsmodel.h"
 #include "bitcoingui.h"
 #include "editaddressdialog.h"
 #include "csvmodelwriter.h"
@@ -20,6 +21,7 @@ AddressBookPage::AddressBookPage(Mode mode, Tabs tab, QWidget *parent) :
     QDialog(parent),
     ui(new Ui::AddressBookPage),
     model(0),
+    optionsModel(0),
     mode(mode),
     tab(tab)
 {
@@ -139,6 +141,11 @@ void AddressBookPage::setModel(AddressTableModel *model)
     selectionChanged();
 }
 
+void AddressBookPage::setOptionsModel(OptionsModel *optionsModel)
+{
+    this->optionsModel = optionsModel;
+}
+
 void AddressBookPage::on_copyToClipboard_clicked()
 {
     GUIUtil::copyEntryData(ui->tableView, AddressTableModel::Address);
@@ -314,6 +321,8 @@ void AddressBookPage::on_showQRCode_clicked()
         QString address = index.data().toString(), label = index.sibling(index.row(), 0).data(Qt::EditRole).toString();
 
         QRCodeDialog *dialog = new QRCodeDialog(address, label, tab == ReceivingTab, this);
+        if(optionsModel)
+            dialog->setModel(optionsModel);
         dialog->setAttribute(Qt::WA_DeleteOnClose);
         dialog->show();
     }