Merge pull request #1 from floodlight/master

Syncing with floodligh/loxigen
Merge pull request #3 from floodlight/master

Keeping master up to date
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge into master from pull request #143:
Make the of() function public/visible LOXI-54 (https://github.com/floodlight/loxigen/pull/143)
javagen.OFPortPortBitmap: add some documentation
Merge branch 'master' of github.com:floodlight/loxigen
.build/push-artifacts: also push tags

The tags for the loxigen-artfacts repository were generated locally
but not sent to github.
Merge into master from pull request #146:
small fixes, push tags in push-artifacts (https://github.com/floodlight/loxigen/pull/146)
pyloxi: use the ofclass subtemplate for messages

The only difference was the special case for the default XID.
pyloxi: use ofclass subtemplate for OXMs
ir: convert version fields to OFTypeMembers

The frontend gets a new OFVersionMember field type, which is lowered to
OFTypeMember when generating the IR (which is when the version is first known).
pyloxi: use OFClass directly

It now includes everything we need except pyname.
pyloxi: create inheritance hierarchy

Virtual classes are generated but currently only serve as superclasses.

Somehow this works without topologically sorting the classes.
pyloxi: generate virtual class unpack methods

This is done completely from the IR now.