Update should-i-commit-the-dependencies-in-my-vendor-directory.md

Add a third option for including vendor dependencies in main GIT repo.
Update should-i-commit-the-dependencies-in-my-vendor-directory.md

Tweak option #3 for including dependencies in a GIT repo.
Clear stat cache after calling filesystem commands
Trim query string from extension when downloading archives
Avoid failing if COMPOSER env var is empty, refs #1720
Merge pull request #1718 from reinink/patch-1

Update should-i-commit-the-dependencies-in-my-vendor-directory.md