Add Patreon button. Needs an icon (used I for now).

gui/MainWindow.cpp

@@ -1015,6 +1015,11 @@ void MainWindow::on_actionReportBug_triggered()
 	openWebPage(QUrl("https://github.com/MultiMC/MultiMC5/issues"));
 }
 
+void MainWindow::on_actionPatreon_triggered()
+{
+	openWebPage(QUrl("http://www.patreon.com/multimc"));
+}
+
 void MainWindow::on_actionMoreNews_triggered()
 {
 	openWebPage(QUrl("http://multimc.org/posts.html"));

gui/MainWindow.h

@@ -85,6 +85,8 @@ slots:
 
 	void on_actionReportBug_triggered();
 
+	void on_actionPatreon_triggered();
+
 	void on_actionMoreNews_triggered();
 
 	void newsButtonClicked();

gui/MainWindow.ui

@@ -74,6 +74,7 @@
    <addaction name="actionReportBug"/>
    <addaction name="actionAbout"/>
    <addaction name="separator"/>
+   <addaction name="actionPatreon"/>   
    <addaction name="actionCAT"/>
   </widget>
   <widget class="QStatusBar" name="statusBar"/>
@@ -268,6 +269,22 @@
     <string>Open the bug tracker to report a bug with MultiMC.</string>
    </property>
   </action>
+  <action name="actionPatreon">
+   <property name="icon">
+    <iconset theme="about">
+     <normaloff/>
+    </iconset>
+   </property>
+   <property name="text">
+    <string>Support us on Patreon</string>
+   </property>
+   <property name="toolTip">
+    <string>Open the MultiMC Patreon page.</string>
+   </property>
+   <property name="statusTip">
+    <string>Open the MultiMC Patreon page.</string>
+   </property>
+  </action>  
   <action name="actionMoreNews">
    <property name="icon">
     <iconset theme="news">