Add "github integrate" task

[zstumgoren]

• Prompts user to select an account for repo creation
• Checks if repo already exists on Github
• Executes git init, git commit -m "Initial commit" and git push to new repo
• Asks user to set privacy level via prompt

Test Scenarios

• Choose default user account
• Choose org account
• Repo does not exist for account
• Repo already exists for account
• Repo created
• Repo already integrated (i.e. it's already been gitified and integrated with Github)

[zstumgoren]

Merged basic Integrate command with tests for py3.5 - 3.7, and initial tox and travis configs. Will likely need to work out kinks in Travis integration.