Fixes test failures and ports the ability to configure JVM options from the kivy repository

These changes accomplish the following:
* Enable compilation under Cython 0.21+
* Port configurability of JVM startup options from the kivy repository
* Package NativeInvocationHandler with the module (this was causing a test to fail, [see this issue](https://github.com/kivy/pyjnius/issues/137) for details)
* Add NativeInvocationHandler to the class path
* Specify the version of the NativeInvocationHandler and test class files to handle cases where the javac version is higher than the JVM version launched by jnius