Intentional changes:
1) Added a decorator implementation of CodeBlockTimer.
2) Wrote a unit test for said decorator using a mock.Mock of
   the storage class.

Side effect changes:
1) Removed dependency on path module.
2) Changed storage import to module-level import (run-time module
   member lookups are helpful for safe patched mocking.)
3) Added test dbs to .gitignore.

Thanks; this was fun.

Add .gitignore file.