netlink module refactoring
Merge branch 'master' into 0.3.x

Conflicts:
	pyroute2/netlink/client.py
netlink: pep8 fix
generic: own socket class
generic: relocate cluster client class
netlink: pep8 fix
docs: new structure (to be filled)
docs: update
nlsocket: encoding/decoding policy management routines
nlsocket: fix docs typos
pyroute2: include IPQ and IPQSocket into the root exports
nlsocket: decode incapsulated error message
pyroute2: include generic netlink into the root exports