loci: generate wire type parsers from the IR

Every virtual class gets a function that reads the discriminator and returns an
object id. If the subclass is a virtual class then the parsing recurses.
loci: remove handwritten wire_object_id_get functions
loci: remove more dead code
loci: switch message parsing to of_header_wire_object_id_get
loci: add missing test for of_object_new_from_message

Also fix embarassing typos in test_of_object_new_from_message_preallocated.
Merge remote-tracking branch 'origin/master' into loci-parser

Conflicts:
	c_gen/c_type_maps.py
	c_gen/templates/of_type_maps.c
Merge into master from pull request #216:
Generate LOCI wire type parsers from the IR (https://github.com/floodlight/loxigen/pull/216)
java_gen: add documentation to string-parsing 'of' methods
add bitwise logical operators and broadcast check

AND, OR, NOT and isBroadcast added to IPAddress
getSubnetBroadcastAddress added to IPAddressWithMask with
convenience method isSubnetBroadcastAddress
check for invalid masks in getSubnetBroadcastAddress in IPAWithMask
make logical oper typesafe and remove code duplication
Merge into master from pull request #220:
add bitwise logical operators and broadcast check (https://github.com/floodlight/loxigen/pull/220)
openflow_input: add bsn_egr_port_group_id extension
Merge into master from pull request #221:
java_gen: add documentation to string-parsing 'of' methods (https://github.com/floodlight/loxigen/pull/221)
java_gen: support of_oxm_bsn_egr_port_group_id

It's basically a class-id, so using that type.
Merge into master from pull request #222:
openflow_input: add bsn_egr_port_group_id extension (https://github.com/floodlight/loxigen/pull/222)
java_gen: make of_aggregate_stats_request.out_group type OFGroup
loci: fix bug in new wire type parsers

Using the unified class's discriminator was incorrect because the discriminator
can change offset and length between OpenFlow versions.

Also added tests that would have caught this bug.
Merge into master from pull request #223:
loci: fix bug in new wire type parsers (https://github.com/floodlight/loxigen/pull/223)
Merge into master from pull request #224:
java_gen: make of_aggregate_stats_request.out_group type OFGroup (https://github.com/floodlight/loxigen/pull/224)