Yothalot-PHP 2.8.0

• First implementation of the Yothalot\Pool class, that allows to wait for the result of multiple jobs at the same time
• Tempdir can now be set using the yothalot.temp-directory ini file setting (default = /tmp)
• Added Descriptors class that encapsulates all descriptors used by a connection
• Split loop and descriptors, to allow future support of multiple amqp connections
• Allow callbacks to be passed to the event loop
• json::object is internally already implemented as a sort of shared-ptr, no need to wrap it into another shared-ptr
• Refactored stuff to make it easier to run multiple jobs in parallel, changed the return value for job::start()
• Added method to fetch a job from a queue without waiting, added method to get pool size
• Allow running the finalizer in the client
• Tempqueue channel is now closed after result has been read, to fix the connection::flush() method that does not expect channels to survive
• When a job is serialized/unserialized, it still is possible to run the finalizer locally
• The _cancelled member was not initialized on construction