Fix linting on Xcode 8

Fixed pod repo push validation and push issues related to Dir.chdir

[Validator] Improve Spec Performance

[Acknowledgements] Prevent crash when license type is nil

[Create] Pass the Pod::version as a ENV var for the configure script to read

Make analyzer skip the embedded target -> host compatibility check for hosts not defined in the Podfile

Improved clarity of title for #5726 summary entry.

Capitalized “Messages” to make clear that it is a product name reference (Mac/iOS Messages.app), and added a verb to clarify that the fix pertains to the end use of CocoaPods as opposed to its integration with something else.

Verify embedded target platform/swift matches its host