Modified BlazModelMeta.java.mvel, add public modifier to instance field
Added SQLite index about VALUE_KIND_KEY_STR
Implemented Filter and Sorter about toString() method
Modified BareDatastore about Sorter argument
Added FetchOptions and Fixed MockKVS
Applied FetchOptions to JdbcKVS
Applied FetchOptions to SQLiteKVS
Applied formatter to KeysDao
Applied formatter to ValuesDao
Modified KeysDao#query and ValuesDao#query for fix "too many variables"
Merge branch 'feature/AddFetchOptions' into develop
Added asSingle method to ModelQuery