* Add Python and Redis submodules, and remove old third-party modules
* Update VS projects (WARNING: references files that do not exist yet)
* Update code & add shims for APIs except AF_UNIX/{send,recv}msg()
* Minor style changes.
* Set logging levels in Makefile using -DRAY_COMMON_LOG_LEVEL=level
* Lower level of some LOG_ERROR messages, log the name of the table operation on failure
* Address rest of Robert's comments
* Fix spurious log message