Add DiffView package

Side-by-side diff viewer.

Currently supports Git only.  Only tested on Sublime Text 3.

repository/d.json

@@ -460,6 +460,17 @@
 				}
 			]
 		},
+		{
+			"name": "DiffView",
+			"details": "https://github.com/CJTozer/SublimeDiffView",
+			"labels": ["Git", "diff", "compare", "difference", "comparison"],
+			"releases": [
+				{
+					"sublime_text": ">=3000",
+					"tags": true
+				}
+			]
+		},
 		{
 			"name": "Diffy",
 			"details": "https://github.com/zsong/diffy",