Resolve LIBZMQ-459

Ref: https://zeromq.jira.com/browse/LIBZMQ-459
Merge pull request #56 from hintjens/master

Backported fixes for LIBZMQ-459
Backported fix for ZMQ-465
Minor code cleanup
Backported fix for ZMQ-465
Merge pull request #57 from hintjens/master

Backported fixes for LIBZMQ-465
Updated doc to allow DEALER-DEALER and ROUTER-ROUTER
Merge pull request #58 from hintjens/master

Addded ROUTER-ROUTER and DEALER-DEALER (back) as valid combinations
Backported fix for addresses on triggered events
Merge pull request #59 from hintjens/master

Backported fix for LIBZMQ-450
Issue 468

XPUB "verbose" mode excludes unsubscriptions
Clarified that SNDHWM is per part, not message
Merge pull request #60 from hintjens/master

Fixed doc for SNDHWM
Fixed ZMQ_SNDHWM description
Merge pull request #61 from hintjens/master

Fixed doc for SNDHWM
Added autogen.sh hint
Merge pull request #63 from hintjens/master

Added autogen.sh hint to INSTALL
Check decoder's state function for NULL before calling it

Fixes bug reported by Peter Friend
(http://lists.zeromq.org/pipermail/zeromq-dev/2012-November/019425.html)
Merge pull request #64 from hintjens/master

Backported fix for LIBZMQ-472
Backported latest socket event framework