Use https for some links

Donations.php

@@ -69,8 +69,8 @@ if ($cur_percent > 100.0) {
 </td><td valign="bottom" width="150px">
     <a class="FlattrButton" style="display:none;" href="http://kxstudio.sourceforge.net/"></a>
     <noscript>
-        <a href="http://flattr.com/thing/1098067/KXStudio" target="_blank">
-        <img src="http://api.flattr.com/button/flattr-badge-large.png" alt="Flattr this" title="Flattr this" border="0" /></a>
+        <a href="https://flattr.com/thing/1098067/KXStudio" target="_blank">
+        <img src="https://api.flattr.com/button/flattr-badge-large.png" alt="Flattr this" title="Flattr this" border="0" /></a>
     </noscript>
 </td><td valign="bottom" width="150px">
     <script src="https://liberapay.com/~42762/widgets/receiving.js"></script>
@@ -90,8 +90,8 @@ if ($cur_percent > 100.0) {
         <input type="hidden" name="cmd" value="_s-xclick">
         <input type="hidden" name="hosted_button_id" value="A8QZW5UPVZGTW">
         <input type="hidden" name="currency_code" value="EUR">
-        <!--<input type="hidden" name="notify_url" value="http://kxstudio.linuxaudio.org/donate/ipn.php"/>-->
-        <input type="hidden" name="return" value="http://kxstudio.linuxaudio.org/donate/thankyou.php"/>
+        <!--<input type="hidden" name="notify_url" value="https://kxstudio.linuxaudio.org/donate/ipn.php"/>-->
+        <input type="hidden" name="return" value="https://kxstudio.linuxaudio.org/donate/thankyou.php"/>
         <input type="hidden" name="rm" value="2"/>
         <input type="image" src="https://www.paypalobjects.com/en_US/i/btn/btn_donate_LG.gif" border="0" name="submit" alt="PayPal">
         <!--<img alt="" border="0" src="https://www.paypalobjects.com/en_US/i/scr/pixel.gif" width="1" height="1">-->
@@ -112,8 +112,8 @@ if ($cur_percent > 100.0) {
             </td></tr>
         </table>
         <input type="hidden" name="currency_code" value="EUR">
-        <input type="hidden" name="notify_url" value="http://kxstudio.linuxaudio.org/donate/ipn.php"/>
-        <input type="hidden" name="return" value="http://kxstudio.linuxaudio.org/donate/thankyou.php"/>
+        <!--<input type="hidden" name="notify_url" value="https://kxstudio.linuxaudio.org/donate/ipn.php"/>-->
+        <input type="hidden" name="return" value="https://kxstudio.linuxaudio.org/donate/thankyou.php"/>
         <input type="hidden" name="rm" value="2"/>
         <input type="image" src="https://www.paypalobjects.com/en_US/i/btn/btn_subscribe_LG.gif" border="0" name="submit" alt="PayPal">
         <!--<img alt="" border="0" src="https://www.paypalobjects.com/en_US/i/scr/pixel.gif" width="1" height="1">-->