[Specification::JSON] Add #to_pretty_json method
[Specification::JSON] Add specs for #to_pretty_json
[Specification] Evaluate a Specification in .from_string in the context of the path parameter
[Documentation] Fix spacing
[Changelog] Add entry for spec eval context
Merge pull request #203 from CocoaPods/seg-podspec-eval-context

[Specification] Evaluate a Specification in .from_string in the context of the path parameter