ref #341 -- added filter for nav_menu_css_class
need to make an /images directory in twentyfifteen theme if it doesn't exist
Merge pull request #376 from jarednova/341_menu_archive

Menu Class Filtering
Fix composer install error

fixes no matching package found due to requiring dev-master of
dannyvankooten/php-router

by default composer has "minimum-stability" set to "stable" now, so you
should not be using dev-master

Cleans composer.json format

Fixes broken indention