Feature: JB/file_exists

[groundh0g]

In my tinkerings, I've found it useful to know if a file exists. For example, if there's an "avatar_400x400.png" use it, otherwise use "avatar_200x200.png".

Example usage:

{% include JB/file_exists file="/404.html" %}
{% if file_exists_result %}Found "/404.html"!{% else %}Did not find "/404.html".{% endif %}

{% assign filename = "/405.html" %}
{% include JB/file_exists file=filename %}
{% if file_exists_result %}Found "{{ filename }}"!{% else %}Did not find "{{ filename }}".{% endif %}

Comments? Thoughts?

[groundh0g]

Merged. Closing issue.