Make tfs.LookupDict pickleable

The auto-generated pickling code would go into infinite recursion.
Copy values from remote process

Beforehand, the objects returned by calls to twiss() etc were only
proxies to remote objects (TfsTable with numpy.arry in them and so on).
Access will generally suffer from bad performance and some operations
on them may fail.
Fix warning: src/cern/cpymad/libmadx.pxd:64:18:

Non-trivial type declarators in shared declaration (e.g. mix of pointers
and values). Each pointer declaration should be on its own line.
Return only basic data types in libmadx.pyx

This module should be only a light wrapper around the MAD-X C-API.
Convenience functions are the responsibility of the madx.py module.
Simplify numpy array creation in libmadx.pyx

Since we are not copying/freeing any data the ArrayWrapper code in
libmadx is unnecessary and only introduces a (minor) memory leak: the
allocated array objects themselves can't be freed due to the call to
Py_INCREF.

Explicitly documenting that libmadx.get_table is not responsible for
copying data resolves #45.
Disable madrange parameter in model.py

The range parameter is currently not implemented in the underlying Madx
class.
Pass arguments directly to Madx methods in model.py

Since the underlying transport was changed, there is no reason any more
to manually put all the arguments in a dictionary.
Remove obsolete imports from libmadx.pyx