PHP5

Today I've maked the second PHPurple release and changed it's status to alpha. The changes, came into it, are:

* fixed zts compatibility
* implemented the loopHeartBeat method
* the runLoop method was changed to set the heartbeat interval
* fixed memory leak on empty alias
* purple.debug_enabled is now boolean

The most interesting on this release is the PurpleClient::loopHeartBeat() story, which is of course implemented with g_timeout_add. Take a look at the new example script to see how it works.