Many changes since master version.
- save/load topologies
- host, controller, switch and link properties
- link actions to set status up/down

kill entire process group in Node.terminate

mnexec already puts the shell into its own process group. Killing the entire
process group cleans up after any background processes the user left running.

Fix error wiki url.

IVSSwitch: bring up lo interface
ok for symmetry - we can probably get rid of this later though

Fixes a couple of compiler warnings

Update Oflops repository in install.sh

Only differences are copyright and log message.

mnexec: getopt bugfix