Added qt as fallback if gtk is not installed on linux

deemix_gui.py

@@ -84,9 +84,18 @@ if __name__ == '__main__':
             'persist_session_cookies': True,
             'cache_path': configFolder
         })
-        webview.start(gui='cef', debug=True)
+        webview.start(gui='cef')
+    if sys.platform == "linux":
+        try:
+            from gi import require_version as rv
+            rv('WebKit2', '4.0')
+            print("Starting with GTK")
+            webview.start()
+        except ValueError:
+            print("Starting with QT")
+            webview.start(gui='qt')
     else:
-        webview.start(debug=True)
+        webview.start()
     conn = HTTPConnection(url, port)
     conn.request('GET', '/shutdown')
     t.join()

requirements.txt

@@ -1,5 +1,5 @@
 deemix>=1.1.2
 flask
 flask-socketio
-pywebview==3.3.1
-cefpython3; platform_system== "Windows"
+pywebview>=3.3.1
+cefpython3; platform_system == "Windows"

requirements_gtk.txt

@@ -0,0 +1,2 @@
+-r requirements.txt
+PyGObject

requirements_qt.txt

@@ -0,0 +1,3 @@
+-r requirements.txt
+PyQt5
+pyqtwebengine