phpredis 2.2.7

This is the tag for phpredis 2.2.7 which will become the
current master on github, with a pecl release to follow
(assuming we don't run into any issues in the meantime).

-- Improvements ---

* Implemented PFADD, PFMERGE, and PFCOUNT command handling
* Implemented ZRANGEBYLEX command (holding off on ZREVRANGEBYLEX
  as that won't be out until 3.0)
* Implemented getMode() so clients can detect whether we're in
  ATOMIC/MULTI/PIPELINE mode.
* Implemented rawCommand() so clients can send arbitrary things to
  the redis server
* Implemented DEBUG OBJECT (@michael-grunder, @isage)
* Added/abide by connect timeout for RedisArray
* Select to the last selected DB when phpredis reconnects

-- Fixes ---

* Fix a possible invalid free in _serialize
* Added SAVE and BGSAVE to "distributable" commands for RedisArray
* @welting -- Fixed invalid "argc" calculation re HLL commands
* Allow clients to break out of the subscribe loop and return context.
* Fixes a memory leak in SCAN when OPT_SCAN_RETRY is enabled.
* @remicollet -- Fix possible segfault when igbinary is enabled.
* Add a couple of cases where we throw on an error (LOADING/NOAUTH/MASTERDOWN)
* Fix several issues with serialization and IGBINARY
* @itcom -- Fix missing TSRMLS_CC and a TSRMLS_DC/TSRMLS_CC typo