Update development workflow

[Zearin]

The scripts for testing, releasing, and publishing haven’t been touched in ages.

I’m going to do a basic setup for the following:

CI Testing

• Travis: Use pyenv (instead of pythonbrew) for CI testing
• Travis: Always use the latest bugfix release for each X.Y version of Python
• Travis: Rename travis-requirements.txt ▶︎ .travis-requirements.txt

Other automation

• Hooks: Use @icefox’s awesome git-hooks for project-wide hooks
• Code checks: Use pylint to check code quality
• Releases: Use GitHub’s Release API
• Version: (Pre-release hook) Validate release versions with semver

Miscellaneous

• Add .editorconfig
• Move metadata from setup.py to pyvows/__meta__.py
• Replace make targets with setup.py commands
  http://www.niteoweb.com/blog/setuptools-run-custom-code-during-install
• Remove references to Crate.io (former Python-package index; now an SQL product)