Merge pull request #149 from pkuxkxjason/next-3.0

support the RANDOMIZED_RESETS option
Bump version to 3.0-alpha7.4
Improves log message in logon process.
Adding a TODO.
Adding a safe_error routine.
source formatting.
Correction for postgresql include path.

Fix #150.
Fix compile warnings.
Merge pull request #151 from sunyc/master

Changes for alpha7.4
Deal with lack of SIGIOT.
Merge pull request #153 from sunyc/master

Deal with lack of SIGIOT.
Unifiy callout, heartbeat and various funciton as an tick_event loop.
Migrate more internal stuff into options_internal.h
Improve hash function for apply cache.

This seems to reduce collisions and should provide better
performance.
Make comment for APPLY_CACHE_BITS more obvious
Added a TODO to handle LPC runtime error more elegantly.
Remove duplicated sig_hup handler.
Clear tick_events queue on exit.
Register auto reclaim_objects() call.
Update travis config.