Add HTTPS column

This closes #159

Initially I have just taken the URL to the API - if it is https:// I
have assumed it does, if it doesn't I have assumed the opposite.

There may be some incorrect but as an initial update I thought that was
the safest way

CONTRIBUTING.md

@@ -10,14 +10,14 @@ community build applications and use free, public APIs quickly and easily. Pull
 
 Current API entry format:
 
-| API | Description | Auth | Link |
+| API | Description | Auth | HTTPS | Link |
 | --- | --- | --- | --- |
-| API Title | Description of API | Does this API require authentication? * | Link to API webpage |
+| API Title | Description of API | Does this API require authentication? * | Does the API support HTTPS? | Link to API webpage |
 
 Example entry:
 
 ```
-| NASA | NASA data, including imagery | No | [Go!](https://api.nasa.gov) |
+| NASA | NASA data, including imagery | No | Yes | [Go!](https://api.nasa.gov) |
 ```
 
 Currently, the only accepted inputs for this field are as follows: