When GTEST_FILTER is not empty, do not run non-Gtest tests. User is filtering on something specific.
ATS plugin: Re-enabled deletion of transaction at transaction close time
Allow for out-of-order transaction destroys
ATS: Force notify request / response finished before destroy
modhtp: Handle NULL request / response headers
Engine various: Handle NULL request / response header
modhtp: Don't trigger _body_data_ex() with NULL if there has been
no acutal body data.
ATS plugin: Don't trigger body data for zero-length blocks.
ib_tx_destroy(): Fixed several bugs in the tx list handling introduced
in previous commit.
ATS: A couple code cleanups
Added IB_TX_FREQ_HAS_DATA and IB_TX_FRES_HAS_DATA flags to the tx flags.
Rule engine: Don't run rules on empty transactions
Managed collections: Don't try to persist empty transactions.
modhtp: Log parser errors for empty responses at DEBUG instead of NOTICE
The server parameter to ib_engine_create() is now const.
Some doxygen cleanups
Added context destroy hook to modhtp; this fixes a memory leak.
Update nginx conn_init to match engine API changes.
 - Bug fix: Ragel's finite state machine must be preserved when include a file in an already occurring parse.
 - Mock Module to track unit test changes.
 - Various fixes not associated with a particular bug, but make the code
   more robust.
Fixing use of save_node before initalization.  Cleanup of goto error handling.

Regarding the use of gotos: intead of a single cleanup label we are
giving each error condition its own label. Because not all error
conditions can be detected (eg ib_cfgparser_push_node failure) we choose
to use a label-per-error condition.