java_gen: add accessor to reader to offactory
Cleanup and rearrangements in Match structure and fields.
1. Added full documentation for the Match interface
2. Added Builder into Match interface and removed the separate class
3. Added ability to declare field prerequisites in the MatchField class and then check that they are
met using a given Match object
4. Fixed some small issues in value types and added a value type for Metadata
Added a naive import cleaning module that looks for imported class name in code and if not found removes
the import declaration (It's not perfect in removing everything like Eclipse but it cannot harm as it may
only miss a redundant import but can't remove a useful one).
Also, changed java model to support multiple test files for a single java class, test files should be:
c_name.data (first test file)
c_name.1.data (second test file)
c_name.2.data (third test file)
and so on.
Added exceptions for JTypes to relate primitive values in OXM input to OFValueType java enum/object types.
Merge branch 'master' of github.com:andi-bigswitch/loxigen
Changed template files to match new Builder interface and compile.
Templates in this commit are still empty, but at least compile.
Added FULL_MASK, NO_MASK constant values for each value type.
Flipped NO_MASK and FULL_MASK, fixed (IPv4|IPv6)WithMask to use constant masks and a typo in Prerequisites.java.
Changed generated types for OFOxmIcmpv6Code,OFOxmIcmpv6Type,OFOxmMplsLabel,OFOxmMplsTc to object types (U8/U32)
to conform with the generics API of OFOxm.
Merge pull request #46 from yotamhc/master

Latest changes in value types, OXMs, Match etc.