ProgressWindow: Fix incorrect sizing

Setting a height/max-height was causing the window not to grow correctly when
rows were added. Whatever the purpose of those styles was in past FF versions,
they're no longer necessary now.

chrome/content/zotero/progressWindow.xhtml

@@ -33,8 +33,7 @@
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
 		xmlns:html="http://www.w3.org/1999/xhtml"
 		title="&zotero.progress.title;"
-        width="300" height="30"
-		style="max-height: 20px"
+        width="300"
         windowtype="alert:alert">
 		
 	<vbox id="zotero-progress-text-box" flex="1" style="padding: 10px">