Lock SwiftProtobuf to 0.4.3 

Merge pull request grpc#295 from rebello95/fix-strict-prototypes Fix -Wstrict-prototypes warning

Update podspec to version 0.5.0. 

Update podspec to 0.4.3. 

Merge pull request grpc#213 from grpc/podspec-validation Fix a few problems found running "pod spec lint".

Merge pull request grpc#201 from MrMage/wait-timeout Add a `timeout` option to blocking `send()` and `receive()` calls

Merge pull request grpc#203 from rebello95/channel-sharing-tests Add ServiceClient tests for shared channels

Update Examples for 0.3.3 

Remove unneeded CountDownLatch class. 

Import file naming code from swift-protobuf to allow consistent file … …naming between the grpc and protobuf plugins. First steps.