Added documentation for 'notebook' support in config.json files. (#84)

* Added documentation for 'notebook' support in config.json files.  Also added a few links to anchor points within the page for easier navigation.

* Updated page to include information about 'starter_value_string'.

* Added in documentation for the 'alt' field to be used in image object configuration.

* Removed a note that was in the wrong spot.

Author: Kevin-MM

_docs/instructor/assignment_configuration.md

@@ -198,8 +198,11 @@ executables.
 
 
 * **field:** ``"testcases"``  
-  **type:** _array of testcase objects_ (defined below)  
+  **type:** _array of testcase objects_ ([defined below](#specification-of-a-testcase))  
   **REQUIRED**
+  
+* **field:** ``"notebook"``  
+  **type:** _array of notebook objects_ ([defined below](#specification-of-a-notebook))  
 
 
 * **field:** ``"assignment_message"``  
@@ -335,6 +338,88 @@ executables.
 * **field:** ``"textboxes"``  
   **type:** _array of textbox objects_  (Described below)  
   **default value:** ``empty``  
+  
+  
+### Specification of a Notebook
+
+
+* **field:** ``"title"``  
+  **type:** _string_  
+  **value:** Title of the item (ex. Question 1)  
+
+* **field:** ``"description"``  
+  **type:** _string_  
+
+* **field:** ``"images"``  
+  **type:** _array of image objects_  
+  
+* **field:** ``"input"``  
+  **type:** _array of input objects_   
+  
+  
+### Specification of an Image Object
+
+
+* **field:** ``"image_name"``  
+  **type:** _string_   
+  **value:** Name of the image file to be displayed.  
+  **default value:** ``""``
+  
+* **field:** ``"alt"``  
+  **type:** _string_   
+  **value:** Specify alternate text that describes the image, for use with accessibility screen readers.  
+
+* **field:** ``"image_height"``  
+  **type:** _int_   
+  **value:** Numeric height in pixels to display the image at.  
+  **default value:** ``0`` _(displays at native image height)_  
+
+
+* **field:** ``"image_width"``  
+  **type:** _int_   
+  **value:** Numeric width in pixels to display the image at.  
+  **default value:** ``0`` _(displays at native image width)_
+
+  
+### Specification of Notebook Input Objects
+
+
+* **field:** ``"type"``  
+  **type:** _string_  
+  **value:** ``"short_answer"``, ``"codebox"``, or ``"multiplechoice"``  
+  **description:** Specifies the type of input to display
+  
+  
+### Specification of a Short Answer box (short_answer)
+
+
+* **field:** ``"label"``  
+  **type:** _string_   
+  **value:** String description of what to write in the short answer box.  
+  **default value:** ``""``
+  
+  
+* **field:** ``"starter_value_string"``  
+  **type:** _string_   
+  **value:** The text to be prepopulated into the input box  
+
+
+* **field:** ``"rows"``  
+  **type:** _int_   
+  **value:** Numeric height of the textbox in rows.  
+  **default value:** ``1``
+
+
+* **field:** ``"filename"``  
+  **type:** _string_  
+  **value:** Specify a filename that the captured input data will be written to
+
+
+* **field:** ``"images"``  
+  **type:** _array of image objects_   
+  **value:** list of the images to be displayed.  
+  **default value:** ``empty``
+
 
 
 ### Specification of a Networked Gradeable
@@ -675,51 +760,7 @@ Moves the mouse to the origin (upper left) of the student’s window.
    ```
 
 
-### Specification of a Textbox
-
-
-* **field:** ``"label"``  
-  **type:** _string_   
-  **value:** String description of what to write in the textbox.
-  **default value:** ``""``
-
-
-* **field:** ``"rows"``  
-  **type:** _int_   
-  **value:** Numeric height of the textbox in rows.
-  **default value:** ``1``
-
-
-* **field:** ``"filename"``  
-  **type:** _string_   
-  **value:** String name of the text file generated by submission of the textbox. (ex. input1.txt)
-  **default value:** ``""``
-
-
-* **field:** ``"images"``  
-  **type:** _array of image objects_ (Described below)  
-  **value:** list of the images to be displayed.
-  **default value:** ``empty``
-
-#### Specification of an Image Object
-
-
-* **field:** ``"image_name"``  
-  **type:** _string_   
-  **value:** Name of the image file to be displayed.
-  **default value:** ``""``
-
-
-* **field:** ``"image_height"``  
-  **type:** _int_   
-  **value:** Numeric height in pixels to display the image at.
-  **default value:** ``0`` _(displays at native image height)_
-
 
-* **field:** ``"image_width"``  
-  **type:** _int_   
-  **value:** Numeric width in pixels to display the image at.
-  **default value:** ``0`` _(displays at native image width)_
 
 
 ### Specification of a Validation Object