Transition away from the header-only library model

[Matthewacon]

fake-jni has grown too large to be a header-only library; compile times are taking much longer than a standard shared library, the header include dependency ordering is too complex to easily make changes to, and the user API is suffering from unclear multiple definition compile-time errors when incorrectly including fake-jni, due to the inline functions and members as part of the library. Furthermore, the startup time and memory complexity of fake-jni, as a header-only library, grows linearly with every translation unit that it is included in, once again, due to the statically allocated inline members and inline functions.

Transitioning to a standard shared library model will solve all of these issues as all statically allocated memory and inline functions will only be defined in a single translation unit, regardless of the include count.