Add database.py tests and refactoring

- Remove test methods that only check function return types

- Create resources folder for common test data like test rss feeds

- Fix database.py query bugs

- Add database folder for database related tests

- Refactor common database fixtures into the database conftest file

- Refactor comments in database.py

- Refactor queries in database.py to have better style and sanitization

- Add comments and examples of the presentation time stamps

- Remove unused functions from database.py

- Add httpretty mock tests for database.py

- Add a database schema upgrade test

- Add tests that check multiple scenarios of each method in database.py

- Replace string % operators with calls to format for nonlog string formatting

- Remove several try/finally statements and replaced them with 'with's

- Fix an exception logging statement which referred to an out of scope value

- Add failure and presentation equality and inequality comparison functions

- Add example of parameterized test with fixtures

- Fix relative path bug from linux convention to multi-platform in
  test_rss_feedparser.py

- Add fixtures based on summer camp 2010 and 2011 stored data

- Add rough copy of new schema

Related #484
Related #667
Related #670