Update README.md
Improve checkout command usability.
Merge pull request #130 from pjcdawkins/fix-branch-wait

Provide a more stable 'branch' command.
Fix git command intended to create AND checkout a branch locally.
Add environment:ip command
Add --pipe option to env:ip
Validate the IP address for IPv4 syntax, and add --max-time.
Allow alternative provider and show curl errors for env:ip
Remove override of doRun() so the help option works.
Remove skipLogin() methods.
Restore welcome command.
Cache environments transparently.
Use the better caching to clean up drush aliases.
Fix undefined var
Add --yes and --no options, replacing --no-interaction.

Replace 'dialog' with 'question' throughout.
Merge branch 'cache-environments' into mine
Merge branch 'fix/help-option' into mine

Conflicts:
	src/Application.php
Merge branch 'feature/env-ip' into mine
Merge branch 'fix-branch-wait--fix-checkout' into mine
Merge branch 'update-readme' into mine