add lua like path search for skynet module

path/?.so;another_path/?.so
Merge pull request #64 from vontio/master

add lua like path search for skynet module
timerBUG

linux系统在特定的时间点，_gettime()会溢出，timer将不会触发timeout事件
Merge pull request #65 from hongling0/master

fix: timer will rewind after 194 days
Merge pull request #66 from puqing/master

optimize the search of empty slot in the hashid_node array
add skynet command MQLEN for debug
Merge branch 'master' of github.com:cloudwu/skynet
bugfix: read cap in lock
Fix Issue #67
driver.drop need 2 argument