Fix compilation of Python bindings when libsqlite3 is not available (and so the class SqliteDataOutput is omitted).

New pybindgen and API rescan.  Extensive API description files changes because pybindgen now handles consts differently.

This adds two example files that will use the Linux
2.6.18 and 2.6.26 stacks provided by NSC.

This adds the hooks to allow the nsc code to be compiled into ns-3 if
the --nsc flag is specified during 'waf configure'.

This adds the core network simulation cradle support
code.

GetAllEndPoints() will be used by the network simulation cradle.
After a wakeup event, all sockets (Endpoints) have to be checked
for state changes.

Require new PyBindGen (now ignores the badly scanned anonymous containers that cause problems on cygwin) and rescan API.

New PyBindGen version and API rescan: adds missing copy constructors, and generates __copy__ methods so that python's copy.copy() works on our objects.

Make copy constructors of some wifi classes private so that pybindgen won't use them (they are not usable)