Add `ack` to ensure request number equal to response number in a redis connection
Add appCron interface
Delete Redis app initAppData implement
Add consistency hash supporting
important update: refactor struct conn and hence no copy demand
Fix multi backup support
Refactor sruct conn
Fix some codes which may cause compiler warning
Remove compiler warning
Change Server.cron_time to struct timeval from time_t

We should enhence time precison in time sensitive places such as redis
latency
Change Server.cron_time update way
Add ll2string and intDictType
Add redisCron
Add redis protocol command identification on read/write attribute
Fix compiler warning and errors
Add redis handling timeout request and timeout redis server because of network slow or crashing
Change Wheatserver version