Added retina support to Mac cursor. HDPI for #362

src/vs/editor/browser/viewParts/lineNumbers/flipped-cursor-mac-2x.svg

+<?xml version="1.0" encoding="utf-8"?>
+<svg version="1.1" id="Layer_1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0px" y="0px"
+	 viewBox="0 0 24 36" style="enable-background:new 0 0 24 36;" xml:space="preserve">
+<style type="text/css">
+	.st0{fill:#FFFFFF;}
+</style>
+<g>
+	<polygon points="8.6,33.1 11.8,23.9 2.2,23.9 23,2.5 23,31.3 17.4,26.1 14.2,35.1 	"/>
+	<path class="st0" d="M22,29.1l-5-4.6l-3.4,9.4l-3.8-1.4l3.4-9.6H4.4L22,4.9 M0,24.9h10.4l-3,8.4l7.6,2.8l3-8.2l6,5.8V0.1L0,24.9z"
+		/>
+</g>
+</svg>

src/vs/editor/browser/viewParts/lineNumbers/lineNumbers.css

@@ -14,7 +14,11 @@
 }
 
 .monaco-editor.mac .margin-view-overlays .line-numbers {
-	cursor: url('./flipped-cursor-mac.svg') 12.6 0, default;
+	/* Specific fix for blurry cursor on hdpi screens in Chrome and Chromium */
+	cursor: -webkit-image-set(
+		url('./flipped-cursor-mac.svg') 1x,
+		url('./flipped-cursor-mac-2x.svg') 2x
+	) 24 3, default;
 }
 
 .monaco-editor .margin-view-overlays .line-numbers.lh-odd {