Updates to miniedit

- Added Save and Load of topologies
- Choosing Reference or Remote controller
- Added Link properties.  Double click on link and set TCLink parameters for 'bw' and 'delay'
- Hosts and switches are now numbered separately
- From Edit->Preferences, you can set the IP Base
- You can export your topology to a mininet custom topology py file.
- add more link opts (max_queue_size, loss)
- started adding right click menu on switch, host and link
- default terminal type in preferences