zloop_poller: control disabling of event handler on POLLERR

Normally a POLLERR flag returned from poll(2) will disable the
event handler after the first callback. For some file types,
POLLERR is not an error situation and this behaviour is
undesirable. To keep the handler enabled despite POLLERR being
returned, define the pollitem like so:

zmq_pollitem_t items [] = {
       { 0, fd, ZMQ_IGNERR|ZMQ_POLLIN, 0 }
};
demo program for using ZMQ_IGNERR patch

also contains a named pipe reading example

Signed-off-by: Michael Haberler <git@mah.priv.at>
Added support for ZMQ_ROUTER_MANDATORY, ZMQ_XPUB_VERBOSE, and ZMQ_DELAY_ATTACH_ON_CONNECT
Merge pull request #80 from mhaberler/pollerr-no-disable

Pollerr no disable
Merge pull request #79 from hintjens/master

Added some missing setsockopts
Make zsockopt robust against out-of-date libzmq versions
Merge pull request #82 from hintjens/master

zsockopts no longer breaks if it hits a ZMQ_ macro that's undefined
Fixed issue #83
Merge pull request #84 from hintjens/master

Fixed issue #83
Improved zthread documentation
Merge pull request #85 from hintjens/master

Improved zthread documentation
Generated documentation
Changes for V1.3.1

* Added zhash_dup, zhash_keys methods
* Added zlist_dup to deprecate zlist_copy
* Cleaned-up use of include files in all classes
* Rebuilt documentation
Generated documentation
Generated documentation
zhash_keys wasn't defined, fixed that
Merge pull request #86 from hintjens/master

Changes for release 1.3.1
Fixed setsockopt.c to work with ZeroMQ/3.2.1
Merge pull request #88 from hintjens/master

Fixed zsockopts to work with ZeroMQ/3.2.1
Added zmutex class