Small changes

docs/api/image-tracker.md

 
 Instantiate an image tracker with the specified `options`.
 
+*Since:* 0.4.0
+
 **Arguments**
 
 * `options: object, optional`. An object with the following keys (all are optional):

mkdocs.yml

     - 'Demos': 'demos.md'
     - 'Learn': 'getting-started/introduction.md'
     - 'API Reference': 'api/ar.md'
+    - 'Guidelines for Images': 'getting-started/guidelines-for-images.md'
     - 'Support my work': 'support-my-work.md'
     - 'License': 'license.md'
   - 'Download': 'download.md'