Added zframe_sendmem + zero-copy version + tests
Added missing header decls from previous pull requests
Fix incorrect return code documentation for zframe_send
Make zsockopt_set_subscribe, ..._unsubscribe and ..._identity take a const char* argument
Merge pull request #158 from ulikoehler/missing_headerdecls

Added missing header decls
Update doc/zframe.txt
Update doc/zsockopt.txt
Merge pull request #157 from ulikoehler/zframe_sendmem

Added zframe_sendmem + zero-copy version + tests
Merge pull request #160 from ulikoehler/zsockopt_const_subscribe

Make zsockopt_set_... take const char* args
Merge pull request #159 from ulikoehler/zframe_send_docfix

Fix zframe_send return code documentation
Added documentation for functions from previous pull requests
Fix linefolding
Merge pull request #162 from ulikoehler/docfix

Add new functions to zframe.txt and zmsg.txt
Moved sendmem functions to zsocket
Fix sendmem docsg
Make socket first argument in zsocket_sendmem functions
Merge pull request #163 from ulikoehler/zsocket_sendmem

Move zframe_sendmem to zsocket
First version of zcurve, with fixed length messages
Cosmetic style fixes
Merge pull request #161 from hintjens/master

First cut of zcurve, plus some cosmetic fixes