Merge required to continue search-results styling with access to the `/search`
route.

Conflicts:
    app.py

Add:
    bitshift/crawler/indexer.py
        -Add a `try-except` block to catch the `UnsupportedFileError` exception.

Add:
    bitshift/crawler/indexer.py
        -Add conditional to remove the full path of a repository if the owner's
        directory contains only one sub-directory.

Add:
    static/js/index.advanced-search-form.js
        -Prevent the user from removing the last input field in an
        advanced-search group.

Rem:
    templates/index.html
        -Remove vestige code accidentally preserved during the c6e5b4f merge.

Conflicts:
    static/js/index.js
    templates/index.html

Add:
    bitshift/crawler/indexer.py
        -Add `parse()` and `insert()` calls to `_insert_repository_codelets()`.

Add:
    bitshift/crawler/(__init__, crawl).py
        -Move `__init__.py` to `crawl.py`, and add a `main` block to allow
        running the crawler via `python -m`.