Use bootstrap theme. Remove progressbar css that no longer applies.

src/WebInterface.cpp

@@ -22,6 +22,7 @@
 #include "ui/PlayerInterface.h"
 #include <Wt/WText>
 #include <Wt/WAnimation>
+#include <Wt/WBootstrapTheme>
 
 struct WebInterface::internal
 {
@@ -33,6 +34,7 @@ WebInterface::WebInterface(const Wt::WEnvironment& env) : Wt::WApplication(env)
 {
     priv_int = new internal;
     this->useStyleSheet(Wt::WLink("/resources/font-awesome/css/font-awesome.min.css"));
+    setTheme(new Wt::WBootstrapTheme());
     setTitle("Arbitrateor - Audio Jukebox");
     enableUpdates(true);
     priv_int->playerUI = new PlayerInterface(this);

src/ui/PlayerInterface.cpp

@@ -38,7 +38,6 @@ PlayerInterface::PlayerInterface(WebInterface* app)
     playControlWidget->setLayout(playControlLayout);
     
     currentTrackProgress = new Wt::WProgressBar();
-    currentTrackProgress->decorationStyle().setBackgroundColor(Wt::WColor("#B20A5E"));
     currentTrackProgress->setFormat("");
     trackProgress = new Wt::WTimer();
     trackProgress->setInterval(1000);