Fix python module shlib links

...and make this more copy-and-paste

    Failure: ImportError ([...]/lib/python/machinekit/hal.so:
    undefined symbol: hal_shmem_base) ... ERROR

    $ ldd [...]/lib/python/machinekit/hal.so
    linux-vdso.so.1 =>  (0x00007fffbfdfe000)
    libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f95693ab000)
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f9568fe5000)
    /lib64/ld-linux-x86-64.so.2 (0x00007f9569854000)
rtapi.pyx:  Fix RTAPILogger.write() string passing

Breaking on Trusty with Cython 0.20

    Cythoning rtapi.c

	def write(self,line):
	    cdef l = line.rstrip(" \t\f\v\n\r")
	    rtapi_print_msg(self._level, "%s", l)
					       ^

    hal/cython/machinekit/rtapi.pyx:109:44: Python object cannot be
    passed as a varargs parameter
Don't generate cython files into version-controlled files

Put files into `attic` directory so that they won't be accidentally
committed after a no-op cython run