Makefile: make java targets more standard

separate the 'regular' make targets from the eclipse-workspace
target
.abat-automerge: add push-artifacts
get_config_reply|set_config: fix enum, support java
java_gen: fix typo in MatchField
Makefile: make wireshark by default
java_gen: fix small formatting error
loxigen-artifacts: address review comments
push-artifacts: validate existence of commit specified in artifacts repo
Merge into master from pull request #134:
.abat-automerge: push artifacts to separate repository (https://github.com/floodlight/loxigen/pull/134)