Adds tmp:init task

* tmp:download - downloads wordpress into tmp directory
* tmp:extract - extracts to target /tmp/wordpress/version dir
* tmp:copy - copies support files to target wordpres dir
* tmp:init - download + extract + copy.

Note: wp-config.php in target directory must be added manually.
Misc cleanup
Adds spec_helper
Adds wpcli_with_local to tmp:copy
Adds wp-cli.yml test support file.
Completes removal of hard coded WordPress path.
Merges branch 'feature/add-tmp-init-tasks' into develop