Fix scaffolding paths

[Lewiscowles1986]

Fixes #188

Approach:

Modify the file-paths copied

notation: source -> dest (vendor path omitted)

• wp-cli/wp-cli/ci/behat-tags.php -> ./utils/behat-tags.php
• wp-cli/wp-cli/features/bootstrap/FeatureContext.php -> wp-cli/wp-cli-tests/features/bootstrap/FeatureContext.php
• wp-cli/wp-cli/features/bootstrap/support.php -> wp-cli/wp-cli-tests/features/bootstrap/support.php
• wp-cli/wp-cli/features/steps/given.php -> wp-cli/wp-cli-tests/features/steps/given.php
• wp-cli/wp-cli/features/steps/when.php -> wp-cli/wp-cli-tests/features/steps/when.php
• wp-cli/wp-cli/features/steps/then.php -> wp-cli/wp-cli-tests/features/steps/then.php
• wp-cli/wp-cli/features/extra/no-mail.php -> wp-cli/wp-cli-tests/features/extra/no-mail.php

Note: Takes passing Travis-CI tests from 49 -> 51 with no new errors (that I've noticed, it's all still some composer version error)

[Lewiscowles1986]

Here are three artifacts from a local build with the copied files. I need to run this on a different machine as it fails on composer after these are generated. I Do not believe this is due to these changes.

wp-cli-test-run-scaffold-package.feature.113-5fb65ebbdbded9.46320105.zip wp-cli-test-run-scaffold-package-readme.feature.59-5fb65eb14f3256.17474245.zip wp-cli-test-run-scaffold-package-readme.feature.84-5fb65eb29e5349.61293041.zip

[schlessera]

Closing this PR, as the changes in wp-cli-tests make it so these files are not needed I a new package repo anymore, so they also don't need to be copied.