Added zctx_new_from_zmq_ctx
Rename zctx_new_from_zmq_ctx to zctx_shadow_zmq_ctx
Added missing CZMQ_EXPORT to new function
Merge pull request #269 from ulikoehler/zctx_new_from

Add function to create zctx shadow from plain ZMQ context
Merge pull request #268 from hintjens/master

Adding regular expression support (zrex)
Added silent rules to build process
Generating all project files from single XML model now

- using same GSL approach as for socket options
- everything is in model/ directory, see model/README.txt
- support added for Android, MingW32, MSVC, CMake
- quite possibly I've damaged MSVC project files