Added a populate_routing method to COMIDPropsAll class.
This reads in all the from and to COMID routing from the FLOW file.
Incorporated the intersect.py code into SFR_classes.py.
Still probably a bit buggy, although it runs! Will check with a backup to be sure all is OK.
Fixed some bugs in the intersect.py translation to classy.
Started incorporating SFR_preproc.py into the SFR_classes.py classes.

Also, identified a problem in SFR_routing_checker.py when circular routing takes place. May not perfectly identify all upstream routing in such a case, but issues a warning.
Merge pull request #9 from mnfienen/classy

Classy