Warming Tux on an Arctic continent

This alpha release of vulcan:

• fixes shell initialization issues with asdf, nvm, and pyenv
• fixes handling of long option parsing when no arguments are given to a script or function
• added a --pre-install-hook to asdf
• calls pipx_ensurepath as part of shell initialization
• added shell initialization to .bashrc, .zshrc, .rc
• fixes brew_get_current_version to account for out of order versions
• adds support for taps in the vulcan-config.yml
• adds support for requires OS dependencies in the vulcan-config.yml
• allows vulcan install to be limited to --only-installers or --only-packages