add Thunderbird client icon

Author: stokito

client_icons.txt

@@ -81,6 +81,7 @@ strophe-api strophe
 swift swift
 talkonaut talkonaut
 telepathy telepathy,empathy
+thunderbird thunderbird
 tigase tigase,stork,beagle,siskin,multi user chat
 tkabber tkabber
 trillian trillian

iconsets.qrc.in

@@ -414,6 +414,7 @@
         <file>iconsets/clients/default/snikket.png</file>
         <file>iconsets/clients/default/spark.png</file>
         <file>iconsets/clients/default/swift.png</file>
+        <file>iconsets/clients/default/thunderbird.png</file>
         <file>iconsets/clients/default/tigase.png</file>
         <file>iconsets/clients/default/tkabber.png</file>
         <file>iconsets/clients/default/uwpx.png</file>

iconsets/clients/default/icondef.xml

@@ -196,6 +196,11 @@
         <object mime='image/png'>swift.png</object>
     </icon>
 
+    <icon>
+        <x xmlns='name'>clients/thunderbird</x>
+        <object mime='image/png'>thunderbird.png</object>
+    </icon>
+
     <icon>
         <x xmlns='name'>clients/tigase</x>
         <object mime='image/png'>tigase.png</object>