move Runtime{State,Lchan} from pySim.filesystem to new pySim.runtime

Those two are really separate concepts, so let's keep them in separate
source code files.

Change-Id: I9ec54304dd8f4a4cba9487054a8eb8d265c2d340
diff --git a/pySim/apdu/__init__.py b/pySim/apdu/__init__.py
index 1d1174d..cc0f701 100644
--- a/pySim/apdu/__init__.py
+++ b/pySim/apdu/__init__.py
@@ -35,7 +35,7 @@
 from construct import Optional as COptional
 from pySim.construct import *
 from pySim.utils import *
-from pySim.filesystem import RuntimeLchan, RuntimeState, lchan_nr_from_cla
+from pySim.runtime import RuntimeLchan, RuntimeState, lchan_nr_from_cla
 from pySim.filesystem import CardADF, CardFile, TransparentEF, LinFixedEF
 
 """There are multiple levels of decode: