use localtime_r instead of localtime

localtime is not thread-safe
fix race condition problem when switching server
modify argument of na_ts2dt
align
completed making neoagent multi-threaded
v0.5.4 released
(fixes #16) remove warnings and add '-Wimplicit-function-declaration' when compiling

implicit declaration of function 'pthread_mutex_lock' and 'pthread_mutex_unlock'
minor cleanups
support for runtime reconfiguration of some parameters
move ConfFile var to neoagent.c
Merge pull request #17 from marktan/master

re-configuration with SIGUSR2
Merge branch 'issues/16'
v0.5.5 released
initial slow query log work
slow query log now takes time in double and measures callbacks separately
fix bug by bokko
add slow query log functionality
move functions for slow query log to slowlog.(c|h)
fix bug(conditional branching is opposite and seconf of slow query log is strange)
add slow query log functionality