Add `Twig#all_branch_names`
Fix getting/setting properties on old branches
Remove unused `Twig#branch_names`
Add tests for `Twig::GithubRepo#initialize`
Add tests for `GithubRepo#origin_url`
Add tests for `GithubRepo#origin_url_parts`
Extract repo URL to a variable in GithubRepo tests
Add tests for `GithubRepo#username`
Add tests for `GithubRepo#repository`
Test HTTPS and Git read-only repo URLs
Prefix `GithubRepo` vars as `@github_`
Abort `twig gh-*` subcommands for non-Github repos
For simplicity, load all of Twig in `twig-gh-open`
`Twig#repo?` -> `Twig.repo?`
Handle non-Git repos gracefully in `twig gh-*`
`#column`: Make first argument required
`#column`: For simplicity, remove subcolumn logic
Add date_time_column_width, property_column_width
Remove unneeded braces
Move `--unset` and `--version` specs up