Provide interface to override default installation resources

[choksi81]

Users may want to customize the resources file that control installed vessels. In Phillipa's specific use case, he wants to be able to override the network I/O cap to perform network measurements.
One approach would be to add a few arguments to Seattle's installers, and pass them onto benchmark_resources.py to perform the actual manipulation.

$ ./install_seattle.sh --resource:netrecv 100000

[choksi81]

I have opted to remove the resource: prefix for the argument, as the resulting command is unnecessarily lengthy. My patch uses the arguments --netsend and --netrecv. Would someone kindly review? It can be found here: https://seattle.poly.edu/attachment/ticket/1406/seattleinstaller.py.patch

[choksi81]

Attachments:
https://github.com/SeattleTestbed/attic/blob/master/TICKET_ATTACHMENTS/seattleinstaller.py.patch