Added del cookie and default path

docs/cookies.md

@@ -32,12 +32,39 @@ async def test(request):
     return response
 ```
 
+## Deleting cookies
+
+Cookies can be removed semantically or explicitly.
+
+```python
+from sanic.response import text
+
+@app.route("/cookie")
+async def test(request):
+    response = text("Time to eat some cookies muahaha")
+    
+    # This cookie will be set to expire in 0 seconds
+    del response.cookies['kill_me']
+    
+    # This cookie will self destruct in 5 seconds
+    response.cookies['short_life'] = 'Glad to be here'
+    response.cookies['short_life']['max-age'] = 5
+    del response.cookies['favorite_color']
+    
+    # This cookie will remain unchanged
+    response.cookies['favorite_color'] = 'blue'
+    response.cookies['favorite_color'] = 'pink'
+    del response.cookies['favorite_color']
+    
+    return response
+```
+
 Response cookies can be set like dictionary values and have the following
 parameters available:
 
 - `expires` (datetime): The time for the cookie to expire on the
                         client's browser.
-- `path` (string): The subset of URLs to which this cookie applies.
+- `path` (string): The subset of URLs to which this cookie applies.  Defaults to 0.
 - `comment` (string): A comment (metadata).
 - `domain` (string): Specifies the domain for which the cookie is valid. An
            explicitly specified domain must always start with a dot.