Squelching WordPress Debug Mode Warnings

Depending on the the users wp_config, they might run their theme development with Wordpress's debug mode set to on.  In this case, the theme will throw strict standards warnings on both site and dashboard.
![image](https://cloud.githubusercontent.com/assets/5032954/5145622/342d3f2c-7159-11e4-8813-31a331290a6d.png)

The method calls I think are easy, and I don't think the argument adjustments would affect your walker either.  Let me know what you think.

Tweaks to fix the theme to work with WP_DEBUG set to on for better troubleshooting.  Explicitly declaring statically called methods as such, and argument definition for the dropdowns walker.