*[bug] emptydb should empty iDB too if idb-enabled
+ get new configrations from command line
* reuses iDBPath string always now
* [bug] allow sdslen(NULL) = 0.
+ Background append only file rewriting scheduled when iDB async writing...
+ dictUpdate
* [bug] dictEmpty(NULL) crash the server
* more detail on redisPanic decrRefCount
* let save and bgsave command support iDB
* clean the dirty if iDBSync in the ServerCron
+ public func flushAllToIDB() to save changes to disk
+ getDictEntryOnDirtyKeys
* [bug] getKeyNameOnIDB append '(null)' into KeyName error
* [bug] [idb-sync=true]aof can not update, because setKeyOnIDB clean dirty
* [bug] memory-leak in setKeyOnIDB when key is a old key
* [bug] deleteOnIDB ensure apply deleted key in dirtyKeys first
* [bug] lookupKeyOnIDB lookup key in dirtyKeys first
* [bug] dbExists should lookup key in dirtyKeys first
* [bug] emptyDb should empty dirtyKeys too
* [bug] flushdb flushall Command means empty database, so clear dirtyKeys too.
* update readme
* disable idb before testing aof
* disable idb before testing rdb
* disable idb before testing maxmemory
* seperate the key name from types for testing sort
* update deps/idb
* waitForBgsave should wait for iDB too.
* update deps/idb
* rename flushDictToIDB to saveDictToIDB
* [bug] makefile should ignore mkdir failed for idb