Finished authentication support in CZMQ (first draft)

* Does not yet support multiple domains
* Adds zcertstore class for managing certificate stores
Show ALLOWED/DENIED outcomes if verbose is set
Simplified white/blacklisting

* Configure via API rather than external file
Added CURVE_ALLOW_ANY to permit anonymous clients over CURVE
Added security pattern examples

* Also fixed makefile for distribution
* Specific LICENSE for security examples -- MIT/X11
Fixed reporting in security examples
Merge pull request #231 from hintjens/master

Finishing up first round of security classes
Fixes to zsys_dir_create and zsys_dir_delete

* The create function was not accurately making multi-directory path
* zfile was depending on incorrect behavior
* Added support for printf formatting in zsys_dir_create/delete
* Added better selftest for zsys_dir_create/delete
Improved certificate serialization API

* Often we want to save/load with a directory path and a filename
  constructed from pieces. This is easier done by passing them as
  a printf format than asking the caller to create the full path
  name.
* Modified zcert_load/save/save_public
* Modified zcertstore_new in same way
Finished security examples
Merge pull request #232 from hintjens/master

Finishing up with security documentation, and examples
Added security examples final cut

* Previous commit wasn't complete, sorry about that...
Merge pull request #233 from hintjens/master

Added security examples final cut
Updated NEWS for 2.0.0
Generated documentation
Merge pull request #234 from hintjens/master

Documentation updates for 2.0.0
Bumped version number for next release, 2.0.1
Updated CZMQ to work with ZeroMQ 4.0

* All socket options as implemented by ZeroMQ/4.0.0
* Removed deprecated zsockopt_set_xxx macros
* Added macro capability to scripts/sockopts.gsl to save code duplication
Merge pull request #235 from hintjens/master

Updates for ZeroMQ/4.0.0
Updated NEWS for release 2.0.1