Qt5 compatibility

This commit squashes all the changes in the Qt5 branch
relative to master.

Backward compatibility with Qt4 is retained.

Original authors:

- Philip Kaufmann <phil.kaufmann@t-online.de>
- Jonas Schnelli <jonas.schnelli@include7.ch>

src/qt/guiutil.cpp

@@ -13,8 +13,12 @@
 #include <QDoubleValidator>
 #include <QFont>
 #include <QLineEdit>
+#if QT_VERSION >= 0x050000
+#include <QUrlQuery>
+#else
 #include <QUrl>
-#include <QTextDocument> // For Qt::escape
+#endif
+#include <QTextDocument> // for Qt::mightBeRichText
 #include <QAbstractItemView>
 #include <QClipboard>
 #include <QFileDialog>
@@ -86,7 +90,13 @@ bool parseBitcoinURI(const QUrl &uri, SendCoinsRecipient *out)
     SendCoinsRecipient rv;
     rv.address = uri.path();
     rv.amount = 0;
+
+#if QT_VERSION < 0x050000
     QList<QPair<QString, QString> > items = uri.queryItems();
+#else
+    QUrlQuery uriQuery(uri);
+    QList<QPair<QString, QString> > items = uriQuery.queryItems();
+#endif
     for (QList<QPair<QString, QString> >::iterator i = items.begin(); i != items.end(); i++)
     {
         bool fShouldReturnFalse = false;
@@ -139,7 +149,11 @@ bool parseBitcoinURI(QString uri, SendCoinsRecipient *out)
 
 QString HtmlEscape(const QString& str, bool fMultiLine)
 {
+#if QT_VERSION < 0x050000
     QString escaped = Qt::escape(str);
+#else
+    QString escaped = str.toHtmlEscaped();
+#endif
     if(fMultiLine)
     {
         escaped = escaped.replace("\n", "<br>\n");
@@ -176,7 +190,11 @@ QString getSaveFileName(QWidget *parent, const QString &caption,
     QString myDir;
     if(dir.isEmpty()) // Default to user documents location
     {
+#if QT_VERSION < 0x050000
         myDir = QDesktopServices::storageLocation(QDesktopServices::DocumentsLocation);
+#else
+        myDir = QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation);
+#endif
     }
     else
     {