Merge pull request #259 from keent/master

Merge from twhittock:enum-groups
Fix build on msvc
Merge pull request #260 from jossgray/master

Fix build on msvc
Problem: Can't retrieve peer header information after first ENTER message.

Solution: Getter method to retrieve header value for a specific peer.
Merge pull request #261 from jossgray/peer-get-header

Problem: Can't retrieve peer header information after first ENTER message
Regenerated documentation
Merge pull request #263 from hintjens/master

Regenerated documentation
Problem: The gsl file to build zyre build system file is out of date
Solution: Remove local zyre model and use zproject

Side-Effects from using zproject:

   * Needed to move the api from zyre.h to zyre_api
   * Only distribute none private header files
   * Moved zre_msg.h into src as this should be private
   * Wrapped private classes in zyre_classes.h which is know generated
   * Private constanst in zyre_classes.h are also generated, see
   project.xml.
Merge pull request #264 from sappo/master

Problem: The gsl file to build zyre build system files are out of date
Problem: Only private constants are listed in project.xml
Solution: Add public constants to project.xml
Merge pull request #265 from sappo/master

Problem: Only private constants are listed in project.xml
Problem: Other projects rely on the private zre_msg.h
Solution: Make the zre_msg.h public again

fixes #edgenet/drops/issue/23
Merge pull request #266 from sappo/master

Problem: Other projects rely on the private zre_msg.h
Problem: autogen.sh has no shebang
Solution: regenerate with latest zproject installed
Merge pull request #267 from jemc/master

Problem: autogen.sh has no shebang
Problem: current shebang does not always work
Solution: change shebang to cross platform one

* Also changed comments on generated files to clarify their origin.

fixes zeromq/zyre#268
Merge pull request #270 from sappo/master

Problem: current shebang does not always work
Problem: Faulty zproject-generated code causes zyre problems in drops
Solution: Regenerate from corrected zproject
Merge pull request #271 from jemc/master

Problem: Faulty zproject-generated code causes zyre problems in drops
Problem: Android needs to provide special LDFLAGS to libtool linking
Solution: Regenerate from updated zproject