Prevent using 'platform get' inside a project directory.
Ensure that 'platform get' to a lower dir will still build the right project.
Merge pull request #191 from pjcdawkins/prevent-recursive-get

Prevent using 'platform get' inside a project directory.
Work around 'operation not allowed' for a stale environment cache.
Merge branch 'development'
Release v1.5.4