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)

In `make nosetests` recipe, execute all tests in one `nosetests` run
so that last line of output represents totals for all tests
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
rtapi.ini:  removed unused TARGET_PLATFORM field

This isn't templated and isn't used by any scripts.
hal_group.pyx:  add group destructor

The signal group object had no destructor method.

The `signal` object's destructor method name is `delete`.  To be
consistent, the `group` object's destructor name is also `delete`.

The former `delete` method removed member signals from the group, so
the `add` and `delete` methods are renamed to `member_add` and
`member_delete`, respectively.
hal_signal.pyx:  Change delete() to a class method

This is consistent with hal ring buffers, which need all refs removed
before they can be deleted.  (Maybe signals should be the same?)
hal_pin.pyx:  fix broken `__repr__` method
hal_ring.pyx:  add destructor function
hal_signal.pyx:  fix Signal error message and __repr__
hal_ring.c:  add ring name to error messages
debian/control:  add python-nose deps
Refactor nosetests

- Run all tests with one command
  - Overall results on bottom line
  - Reduce realtime setup/teardown time
- Provide examples for future test authors
  - Use `nosetest.assert_*` functions
- Simplify test writing where possible
  - RTAPITestCase class makes RTAPI connections trivial
  - Reduce interaction between tests with HAL check function
    - FIXME:  how to run this automatically between modules?
- Adopt proboscis with hierarchical test dependencies
  - Tests may be ordered
  - Skip tests whose dependencies fail