loci: chunk multiple classes into each C file

Parsing headers was taking more than half of the compile time for many classes.
By putting multiple classes into a single C file we amortize the cost of header
parsing. These C files are still much smaller than the old loci.c.

I also experimented with chunking the list and header class files, but there
are relatively few of these and so there was little gain.

The code size reduction is presumably due to better sharing of code between
similar classes. Since the classes are sorted by name before chunking the
action, instruction, etc inheritance hierarchies will be grouped together.

Results:
time make -j4 loci.a: -44% (27.4s to 15.4s)
strip loci.a && du -sh loci.a: -25% (2.3 MB to 1.7 MB)
adding instruction_id type for table feature prop types
adding of_instruction_id_to_object_id
adding instruction_id funcs
removing print statement
adding return statement
Merge into master from pull request #210:
loci: chunk multiple classes into each C file (https://github.com/floodlight/loxigen/pull/210)
fixing bad arg
loci: decide members to ignore in tests using the IR

This prevents the test from trying to set type members.
removing print statements
Make leading zeroes optional in the string passed to HexString.toLong

- applies to the individual colon-separated byte components of the string
- for example, you can now use "1:2:3:4:5" instead of "01:02:03:04:05"
- also added back the unit tests for HexString and added some new tests
Merge into master from pull request #214:
loci: decide members to ignore in tests using the IR (https://github.com/floodlight/loxigen/pull/214)
Use Short.parseShort instead of valueOf to avoid boxing
Merge pull request #215 from vaterlaus/master

Make leading zeroes optional in the string passed to HexString.toLong
Merge into master from pull request #213:
Adding unpadded Instruction Ids for ofp_table_features_prop_instructions* (https://github.com/floodlight/loxigen/pull/213)
Merge pull request #8 from floodlight/master

Merge from floodlight/master