Fixed SearchBar layout and icons

This is almost a rewrite of the Search function on the WebView
the old code had a few uneeded things, mostly being a subclass
of QMainWindow instead of the QWebView - this makes the code
use a tiny bit less ram.

The SearchBox was also moved to an own class ( we can use it
later to filter the contents of the DiveList for instance )

and a forced use of the pixmaps for the Mac and Windows platform
was added.

Signed-off-by: Tomaz Canabrava <tomaz.canabrava@intel.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-ui/mainwindow.cpp

@@ -706,7 +706,7 @@ void MainWindow::on_actionUserManual_triggered()
 {
 #ifndef NO_USERMANUAL
 	if (!helpView) {
-		helpView = new UserManual(this);
+		helpView = new UserManual();
 	}
 	helpView->show();
 #endif