link error:missing libczmq
Merge pull request #471 from catinred2/build_error

link error:missing libczmq
when a worker expires, purgeWorkers does not handle the removal properly.
because the order that workers enters the waiting deque may infect the removal.
missing import
Merge pull request #473 from catinred2/purgeWorker

purgeWorker bug fix
Adapt rrbroker.hs to use poll, not proxy

The examples in other languages use 'poll', because 'proxy' is
only introduced in one of the following sections.
Merge pull request #475 from markus1189/master

Adapt rrbroker.hs to use poll, not proxy
The API for zmq_poll() was changed; timeout is now in milliseconds
Remove memory leak
ROUTER sockets have problems routing if their peers don't have an Id set on their socket
* If the list of workers started with one that wasn't expired then no expired workers would be removed
* Remove performance penalty of repeatedly calling s_clock()
Remove compiler warning of pointless code: testing whether an unsigned var is positive
Clarify example by removing pointless code: destructors always destruct their member containers
msg::unwrap() returns reference to memory that may be deleted by msg::pop_front()

wrap/unwrap() are used to manage string identifiers and so, like most usage of this function, maintain the memory's lifetime via a std::string
* Use C++ containers more appropriate to the task of queuing or random-access/deletion
* Fixed: Workers objects are owned by the broker and, unless idle, leaked upon destruction
* Fixed: Service objects were leaked upon destruction
* When there are multiple workers per service, dispatch a request to the most recently seen idle worker; others might be about to expire and the request will be lost
Code cleanup

* Removed unused predeclaration of broker class
* Friend classes in C++ usually imply incorrect architecture; the services and workers are purely structs used internally by the broker
* Removed virtual-keyword from destructors when the objects are only for internal consumption
* Removed redundant comments
* Removed redundant destructor
* Added appropriate public/private rules for the broker member functions, to aid comprehension of what is internal and vice-versa
Fix indenting (tabs vs spaces) of my pull request
Merge pull request #476 from bmdgarthh/master

C++ MajorDomo example now works for zmq 4.x / bugfixes
[PHP] Fix mdbroker memory leak + incorrect number of workers bug
Merge pull request #477 from recipe/php-mdbroker-memory-leak

[PHP] Fix mdbroker memory leak + incorrect number of workers bug