Alow Asset::find_file usable by twig

Allow for example to add a favicon to your page : {{ base_url() ~ asset_find_file("favicon.png", "img") }}
Merge pull request #68 from daidais/patch-1

Alow Asset::find_file usable by twig
bumped the docblock version to 1.7
Add markdown parse.
Merge pull request #69 from web2citizen/1.7/develop

Add markdown parse.
corrected file permissions
Backported '1.7/develop' into 1.6/master