Merge branch 'feature/issue95' of https://github.com/Hainish/securedrop into Hainish-feature/issue95

Conflicts:
	.gitignore
	securedrop/example_config.py
	setup_ubuntu.sh

This merge changes the default database settings so mysql is not required for
development (use the built-in sqlite instead). It also integrates the database
with the tests, using a temporary sqlite database instead of re-using an
existing databsae, which could cause problems.

If you experience errors related to missing tables after updating, make sure
you've updated your config with the database settings, then run `python -c
"import db; db.create_tables()"`.
Merge branch 'Hainish-feature/issue95'
make sqlite the default database

I lied in the previous merge commit's message. This commit actually makes
sqlite the default database. This reduces the number of dependencies for the
development environment because sqlite is included with Python.
clean up dev setup script, config, and .gitignore
Merge branch 'master' of https://github.com/freedomofpress/securedrop into mysql-tagging

Conflicts:
	.gitignore
	securedrop/example_config.py
	setup_ubuntu.sh