Add an example which builds against a second target and references code. This is more a CI test than an example, though.

Copy headers first then build Pod. This ensures that Pod sources have access to the same header dir structure. Fixes #70.

Always copy headers to ./Pods instead of using the PRODUCT_NAME, which changes for each Pods target. Fixes #75.

The `source_files`, `resources`, and `clean_paths` attributes can take Rake::FileList instances too.

+ autoload for :Config, :Workspace now points to the xcodeproj lib code so as to not trigger loading of MacRuby related code

Add a rake task to open all example workspaces in Xcode. For some reason workspace schemes don’t seem to survive a SCM roundtrip.

Allow a user to define a post install hook in the Podfile, which allows her to customize the generated Xcode project. Closes #56.

Add MacRubySample to the rake build_examples task, now that it can
specify that it needs garbage collection support.

Don’t copy podspecs to the Pods dir, instead generate a Podfile.lock file, which also lists specs from outside spec repos. Closes #47.

Renamed links to alloy/cocoapods to CocoaPods/CocoaPods and also alloy/cocoapods-specs to CocoaPods/Specs.