Detect changes to PBXLegayTarget during build up-to-date checking

[Daniel Lacasse]

As a user building Xcode targets using Gradle, I want the Gradle tasks representing the Xcode targets to be out-of-date only when its build specification change during an incremental build so I can have accurate feedback.

Acceptance Criteria

• Any changes to the product type. It usually means deleting and adding a different target with the same name. To narrow it down to the product type, we must find two target types with the same configuration.
• Any changes to the product name.
• Any changes to build phases that include ordering, adding and removing (separate issues handle the specification of each build phase)
• Any changes to effective build settings (including project's build settings that are not overwritten)