Merge pull request #113 from hintjens/master

Finised self tests, added man pages
Merge pull request #117 from hintjens/master

Removed ghost files, fixed include version check
Merge pull request #119 from hintjens/master

Dependency fixed to CZMQ 2.1.0+
updated chat to use new zyre api
Merge pull request #120 from sappo/master

updated chat to use new zyre api
wrapped message data into an own structure
moved message wrapper into own c file
Merge pull request #121 from sappo/master

wrapped message data into an own structure
added get header by name; added message command defines
updated header method descriptions
Merge pull request #122 from sappo/master

zyre_msg api extended
renamed zyre_msg to zyre_event so it wont be confused with zre_msg
Merge pull request #123 from sappo/master

renamed zyre_msg to zyre_event so it wont be confused with zre_msg
Fixed install of public API

- zyre.h now also includes zyre_event.h
- internal headers files no longer installed