Move border-radius from #main to .window elements to fix radius once …

…and for all

#537 only fixed it on chat windows,
but for some browser-specific display bug/reason not on settings, login, ...

client/css/style.css

@@ -587,11 +587,8 @@ button {
 }
 
 #main {
-	background: #fff;
-	border-radius: 2px;
 	bottom: 4px;
 	left: 220px;
-	overflow: hidden; /* Without this, border-radius has no effect */
 	position: absolute;
 	right: 5px;
 	top: 4px;
@@ -651,6 +648,7 @@ button {
 
 #windows .window {
 	background: #fff;
+	border-radius: 2px;
 	bottom: 0;
 	display: none;
 	left: 0;