add more logs for investigate crash
implement watch point
refactor watchpoint.lua and implement correct 'untrap'
change travis.yml to test multiple version of luajit
make signal handler thread local
make ffi.load thread safe (not 100% sure but dlopen may not thread safe)
execute multiple test for travis
Merge pull request #8 from umegaya/umegaya/feature/test4

Umegaya/feature/test4 travis build passed.