not detecting various imports and missing cycles

Hi,
it seems the tool doesn't process all the import syntax correctly. Not sure which ones it skips but I recommend checking into it:

import Package [as newname]
from Package import sub [as newname]
from .. import relativething [as newname]
from Foo import *

I don't know if the cycle detection is buggy or that the tool misses some imports (or both), but it doesn't find any cycle at all in my [Pyro4 ](https://github.com/irmen/Pyro4) project. But there sure are cycles! See https://github.com/irmen/Pyro4/issues/148 (the graphs are generated by my own cycle analisys tool + graphviz btw)