General housekeeping update.

- Bump version to 0.6.0
- Add template functions to merge dictionaries for loading JSON data inside them
- Add extension management separate from MIME type
- Make the `tembed` processor which runs a generic jinja template through embedding in the template

pixywerk2/defaults/chains.yaml

@@ -8,7 +8,14 @@ default:
 templatable:
     extension: null
     chain:
-        - jinja2
+      - jinja2
+
+# Any object that needs jinja and to be embedded in a parent template
+tembed:
+  extension: null
+  chain:
+    - jinja2
+    - jinja2_page_embed
 
 # Markdown, BBCode and RST are first run through the templater, and then
 # they are processed into HTML, and finally embedded in a page template.