0.3.0

• rules_swift now requires Bazel 0.16.0.
• Linux users must now set CC=clang in their environment to link swift_{binary,test} targets.
• Fixes cross-repository references among protos and well-known types (thanks @steeve!)
• Fixes module name derivation for targets containing . (thanks @gwik!)
• Serializes debugging options into .swiftmodule files until a proper path remapping solution is available.
• Exposes common attribute sets in swift_common to make it easier to write custom Swift rules.
• .swiftdoc files are now propagated by SwiftInfo.
• Additional bug fixes and refactorings.