[Memcache] 1. Change expiring calculation from start of inserting to the last access time. 2. Change API interface. NewMemcache accept from no parameter to one parameter "checkInterval"
[Memcache] 1. Change expiring calculation from start of inserting to the last access time.
2. Change API interface. NewMemcache accept from no parameter to one parameter "checkInterval"

hoveychen/go-utils