Reduce projection label footprint

Don't block interaction.

Author: slowe

0.7.0/virtualsky.js

@@ -1624,12 +1624,12 @@ VirtualSky.prototype.selectProjection = function(proj){
 				.css({
 					'position':'absolute',
 					'padding':0,
-					'width':w+'px',
-					'height':h+'px',
-					'top':'0px',
-					'left':'0px',
+					'height':'2em',
+					'top':'50%',
+					'left':'50%',
+					'transform':'translate3D(-50%,-50%,0)',
 					'text-align':'center',
-					'line-height':h+'px',
+					'line-height':'2em',
 					'z-index':20,
 					'font-size':'1.5em',
 					'display':'block',