tools: fix linker error with newer libtool
cython: Make LockdownServiceDescriptor inherit from Base, since it calls self.handle_error
cython: Add read() method to AfcFile
cython: Initialize some pointers to NULL
cython: Add Afc2Client class to allow jailbroken filesystem access
cython: Explicitly cast ssl_enabled when calling lockdownd_start_session
cython: Update declaration for LockdownServiceDescriptor to match definition