Could use a better directory structure, too. Assets should be in a different folder, things like the walker should be in a lib/includes folder.
Being a starter theme, it doesn't make sense to just reference the Bootstrap CSS from a CDN. Shouldn't you have the LESS files so people can easily make changes without having to do overrides in their CSS?
ps. It's "WordPress", not "Wordpress" (http://codex.wordpress.org/Function_Reference/capital_P_dang...)
Disclaimer: I made Roots (http://roots.io), a Bootstrap starter theme that's been around for a while