Code refactor, support multiple gateways and non-SAML authentication (#9)

* Code refactor

* Update README.md

GPClient/gpgateway.h

@@ -0,0 +1,26 @@
+#ifndef GPGATEWAY_H
+#define GPGATEWAY_H
+
+#include <QString>
+#include <QMap>
+
+class GPGateway
+{
+public:
+    GPGateway();
+
+    QString name() const;
+    QString address() const;
+
+    void setName(const QString &name);
+    void setAddress(const QString &address);
+    void setPriorityRules(const QMap<QString, int> &priorityRules);
+    int priorityOf(QString ruleName);
+
+private:
+    QString _name;
+    QString _address;
+    QMap<QString, int> _priorityRules;
+};
+
+#endif // GPGATEWAY_H