[Update] (_config.yml) page defaults, add cdn var

Make Jekyll future friendly.

Set page defaults in (_config.yml). Add (cdn) variable, because relative
paths are better than global paths.
[Update] (./javascript/util/*), (.ie10-fix.js)

Update documentation headers for consistency.
[Add][mv] (./_plugins/*)

Added autocomplete snippets for Octicon and Font Awesome html icons.

Add:
* tag_fawesome.rb
* tag_octicon.rb

Rename for better navigation.

Move:
ternary_filter.rb -> filter_ternary.rb