Add loopback port to l2gre vport.
Merge remote-tracking branch 'upstream/master'
loci: remove minimum wire buffer allocation size

This hasn't been useful since writable wire buffers were changed to be
allocated at maximum size. This code was causing excessive memory usage in
Indigo when storing the instruction list, which is often only around 16 bytes.
Removing this code saves us 17% memory usage and increases flow-add performance
by 9%.
Merge into master from pull request #286:
loci: remove minimum wire buffer allocation size (https://github.com/floodlight/loxigen/pull/286)
Merge into master from pull request #285:
LOXI-59: IPAdddress hould have a factory function for InetAddress (https://github.com/floodlight/loxigen/pull/285)
Merge remote-tracking branch 'upstream/master'
Add a flag for l2gre loopback.
Merge into master from pull request #281:
Add loopback port to l2gre vport. (https://github.com/floodlight/loxigen/pull/281)
IPAddressWithMask should have a contains method taht can take any IPAddress
add exception test