Recursively processes dependent frameworks to ensure all vendored frameworks are added to the targets xcconfig

[Repo Command] Handle add repo mkpath exception

Don't be discriminatory, extend the scope of rescued exceptions to
StandardError.

Informative exception message was changed in production code but hadn't
been updated in the corresponding test.

Specify what the "repos" directory corresponds to.

It could be helpful to have more details on the original exception for
troubleshoot purposes.

Handling the SystemCallError exception made the body of the run method
a bit busier. Break down the implementation in smaller private methods
for better readability and maintainability.

Creating the "repos" directory when adding a new pod repo my fail due
to system-related errors. For example if the user doesn't have write
permissions to the ~/.cocoapods directory.
Handle the SystemCallError exception to fail gracefully by raising an
Informative exception.

Fixes #4177

[Analyzer] Don't require platform for podless targets when not integrating

Integrate Code of Covenant 1.2.0 changes

Use the more abstract `empty?` method. It excludes inherited
dependencies which is enough for this validation.
Add test where the target inherits the platform from its parent to
ensure the validation passes in this case as well.

When using the '--no-integrate' option, it's not required to check that
the `platform` is specified if the target doesn't have any declared
dependencies.

Fixes #3151

Clear out PRIVATE/PUBLIC_HEADERS_FOLDER_PATH

This fixes an issue with archiving introduced by changing header
accessibility attributes.

Fixes #4119

[PodTargetInstaller] Dont set the dylib version settings

[Installer] Print a post-install message

[EmbedFrameworksScript] Only manually copy swift runtime libs in Xcode 6

Add `tvos` as a new platform

[Analyzer] Build scoped pods once for each target definition