LambdaRuntime v0.2.0

This Version changes everything. Sorry. But growing up always comes with a pain.

• New package name: swift-lambda-runtime. The library is now called LambdaRuntime (#11)
• The Runtime now only has one handler function. This is more in line with the go sdk. The developer still has the option to specify different handler methods by using the env variable _HANDLER
• The runtime is now intended to be used with the amazonlinux-swift project. That is why the makefile to extract Swift libraries from the Ubuntu Swift Dockerimage has been removed.
• swift-base64-kit has been added as a dependency to support future Event types.
• It is possible now to not return a result from the function (#10)
• The synchronous interface has been removed.
• The documentation has been changed to reflect the changes.
• The documentation explains how to create a development image (#9)