Added two internal stylesheets:

- qss.default - This file is used as default for all stylesheets (e.g. the frames of the AvatarWidget) and can be overloaded from the selected stylesheet
- Standard.qss - The standard stylesheet for the current look of RetroShare. More internal stylesheets can be added.
The plan is to move nearly all internal stylesheets to the files Standard.qss/qss.default. After that the "empty" stylesheet should represent the system theme of the os.

git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@5467 b45a01b8-16f6-495d-af2f-9b41ad6348cc

retroshare-gui/src/rshare.h

@@ -79,6 +79,8 @@ public:
   static bool setSheet(QString sheet = QString());
   /** Loads stylesheet from external file **/
   static void loadStyleSheet(const QString &sheetName);
+  /** get list of available stylesheets **/
+  static void getAvailableStyleSheets(QMap<QString, QString> &styleSheets);
   /** Recalculates matching stylesheet for widget **/
   static void refreshStyleSheet(QWidget *widget, bool processChildren);