Removes emptry string defaults

package.json

@@ -85,7 +85,7 @@
                 },
                 "gitlens.blame.annotation.dateFormat": {
                     "type": "string",
-                    "default": "",
+                    "default": null,
                     "description": "Specifies the date format of how absolute dates will be shown in the blame annotations. See https://momentjs.com/docs/#/displaying/format/ for valid formats"
                 },
                 "gitlens.blame.annotation.message": {
@@ -293,7 +293,7 @@
                 },
                 "gitlens.statusBar.dateFormat": {
                     "type": "string",
-                    "default": "",
+                    "default": null,
                     "description": "Specifies the date format of how absolute dates will be shown in the blame status bar. See https://momentjs.com/docs/#/displaying/format/ for valid formats"
                 },
                 "gitlens.advanced.caching.enabled": {
@@ -833,6 +833,7 @@
         "vscode:prepublish": "tsc -p ./"
     },
     "dependencies": {
+        "applicationinsights": "^0.19.0",
         "copy-paste": "^1.3.0",
         "ignore": "^3.2.6",
         "lodash.debounce": "^4.0.8",
@@ -844,6 +845,7 @@
         "tmp": "^0.0.31"
     },
     "devDependencies": {
+        "@types/applicationinsights": "^0.15.33",
         "@types/copy-paste": "^1.1.30",
         "@types/mocha": "^2.2.40",
         "@types/node": "^7.0.11",