Basic API and ME2 support

• DLL should now be able to use the ModEngine2 extension features to bootstrap itself early when loaded using ME2's external_dlls config option
• Simple public C API void* adjust_param_ptr(void*) exported, which can be used to safely access or modify param data while the DLL is active. Simply pass a pointer to (potential) param data to this function once before accessing it to make sure it is correctly adjusted. If using C++, a light wrapper around it can be found here.