Install pods recursively.

Find a test describing the behaviour in the commit.

I have a workspace with a podfile in a subdirectory. The workspace contains a private library, a Mac harness and an iOS harness. The iOS harness is using the podfile. I want Cocoapods to pod install in the top level directory by searching recursively for a podfile, then changing to that directory and running a pod install. This would benefit projects which have a podspec which needs installing and a sample project. We could suppress it using '--no-recursive' or even offer an environment variable.