Unescape cookiecutter vars in base.html template.

Cookiecutter variables don't get replaced inside a raw block,
so we need to turn off raw temporarily.
Use `project_name` in base.html navbar.

Project name is a better, public-facing name than repo name.
Merge pull request #32 from toffer/unescape-cookiecutter-vars-in-template

Unescape cookiecutter vars in base.html template.