Allow Qt to wrap long tooltips (fixes #1063)

Implemented without having to touch any translation: by listening for QEvent::ToolTipChange events, then rewriting the tooltips to prefix `<qt/>` if it is not yet rich text.

src/qt/bitcoin.cpp

@@ -6,6 +6,7 @@
 #include "walletmodel.h"
 #include "optionsmodel.h"
 #include "guiutil.h"
+#include "guiconstants.h"
 
 #include "init.h"
 #include "ui_interface.h"
@@ -164,6 +165,9 @@ int main(int argc, char *argv[])
     Q_INIT_RESOURCE(bitcoin);
     QApplication app(argc, argv);
 
+    // Install global event filter that makes sure that long tooltips can be word-wrapped
+    app.installEventFilter(new GUIUtil::ToolTipToRichTextFilter(TOOLTIP_WRAP_THRESHOLD, &app));
+
     // Command-line options take precedence:
     ParseParameters(argc, argv);