Added PATCH verb end point for annotation op

Added new PATCH verb annotation endpoint

Removed unwanted fmt

Added test cases for PATCH verb annotation endpoint

Fixed formatting issue

Check arr len before proceeding

Updated doc to include PATCH verb annotation endpt

docs/sources/http_api/annotations.md

@@ -160,15 +160,18 @@ Content-Type: application/json
 }
 ```
 
-## Update Annotation
+## Replace Annotation
 
 `PUT /api/annotations/:id`
 
+Replaces the annotation that matches the specified id.
+
 **Example Request**:
 
 ```json
 PUT /api/annotations/1141 HTTP/1.1
 Accept: application/json
+Authorization: Bearer eyJrIjoiT0tTcG1pUlY2RnVKZTFVaDFsNFZXdE9ZWmNrMkZYbk
 Content-Type: application/json
 
 {
@@ -180,6 +183,28 @@ Content-Type: application/json
 }
 ```
 
+## Update Annotation
+
+`PATCH /api/annotations/:id`
+
+Updates one or more properties of an annotation that matches the specified id.
+
+**Example Request**:
+
+```json
+PATCH /api/annotations/1145 HTTP/1.1
+Accept: application/json
+Authorization: Bearer eyJrIjoiT0tTcG1pUlY2RnVKZTFVaDFsNFZXdE9ZWmNrMkZYbk
+Content-Type: application/json
+
+{
+  "time":1507037197000,
+  "timeEnd":1507180807095,
+  "text":"New Annotation Description",
+  "tags":["tag6","tag7","tag8"]
+}
+```
+
 ## Delete Annotation By Id
 
 `DELETE /api/annotations/:id`