Generic Entry Point for Java Lambdas

This release adds support for generic entry points for Java Lambdas, this give you the ability to wrap your methods with IOpipe without needing to modify your existing code.

Information on the usage of generic entry points is located at https://github.com/iopipe/iopipe-java/tree/v1.7.0#generic-entry-point-wrappers.

• Added a generic entry point handler which allows you to more easily wrap methods without needing to write wrappers as needed.
• Added run() methods which take RequestHandler and RequestStreamHandler to IOpipeService to make manual wrapping easier.
• IOpipeExecution.currentExecution() will now always return a value to make the wrapper easier to use when there is no current wrapper to prevent NullPointerExceptionss.
• Project dependencies have been updated.
• Better handling of recursive IOpipeService.run() calls.
• When RequestStreamHandler is wrapped report the exception that the wrapped method throws rather than reporting the exception that is used to wrap it.
• Fixed a bug where the Process ID call was not valid.
• Organized the README.
• Deprecated:
  • The methods IOpipeExecution.plugin() that take method handles has been deprecated.
  • The class IOpipeMeasurement has been deprecated.