of it's own, and cover it's functionality with some specs.

of extending it.

especially around linking of header files and tracking header search paths.

throughout the installation process.

Have downloaders responsible only for cleaning up their own paths, move clean up of other paths
into LocalPod itself.

The Sandbox represents the entire contents of the POD_ROOT (normally SOURCE_ROOT/Pods). A LocalPod represents a pod that has been installed within the Sandbox.

These two classes can be used as better homes for various pieces of logic currently spread throughout the installation process and provide a better API for working with the contents of this directory.

So far I've just refactored the downloaders to use them.

Match IPHONEOS_DEPLOYMENT_TARGET build setting with deployment_target option in generated Pods project file

Match IPHONEOS_DEPLOYMENT_TARGET build setting with deployment_target option in generated Pods project file

Which might not be the case if a pod is part of another pod.

Fixes #130.