setvar: Do not remove values, but edit them. Removing them caused elements to be incorrectly removed.
modlua: Implement `LuaSet <mod name> <setting> <value>` directive.
engine/logger.c: Flush each log message in default writer.
rule_engine: Add rule engine hooks: pre/post rule/operator/action. (RNS-761)
lua: Rename StrSig (Streaming Signature) to StrRule (Streaming Rule).
lua: Add aliases for 0.8.x compatibility.
txlog: bring txlog within trafficserver/ironbee.c to where ats-txlog was
before txlog rewrite.
logger: Format function is now a struct that includes a free() function.

The previous code required the ib_logger_record_fn_t to know how free
records create by the ib_logger_format_fn_t. This is fragile and could
result in memory leaks.

This commit changes the logger pointer stored from the function pointer
(ib_logger_format_fn_t) to ib_logger_format_t, which contains a format
function pointer, its callback data, and a free function and its
callback data. The logger API will call the free function (if it is
defined) after each message has been passed to the ib_logger_record_fn_t
function.
logger: Update server plugins to use new ib_logger_format_t.
logger: Update modules to use new ib_logger_format_t.
log_pipe.c: Exit with error on no memory condition (use rc value).