Add Phalcon\Cache\Backend\Redis
Implemented Phalcon\Db\Dialect\Sqlite
Added the reference to action Phalcon\Db\Reference.
Remove FIRST of addColumn
Merge pull request #2601 from karakurihiden/2.0.0-db-reference

Added the reference to action Phalcon\Db\Reference.
Merge pull request #2602 from karakurihiden/2.0.0-db-sqlite

Implemented Phalcon\Db\Dialect\Sqlite
Merge pull request #2584 from dreamsxin/redis_2.0

Add Phalcon\Cache\Backend\Redis