Calculate provisioning time in provision.sh
Move mockery to stable 0.8.0, at least temporarily
No need to update Composer on every provisioning
Refactor handling of Composer to be version based

More in line with how a provisioning script should handle things. If the expected version of Composer is not installed, either install it or update to that version. If the expected version is installed, don't waste time looking for the update.
Check for status of various vvv-phpunit dependencies before installing

Ideally we would check for version numbers as well, but the bash output just wasn't cooperating. I know this somewhat defeats the purpose of having dependencies managed by Composer itself, but it's sooooo slooooow waiting for it to hunt down updates. I'd rather tell it to only update when a version number does not yet exist.