Merge pull request #275 from sappo/master

Problem: Switch to zproject broke doc build
Problem: zproject was generating zyre_prelude.h

Solution: fix zproject, and regenerate project here.
Problem: lagging behind zproject

Solution: generate project and store results.
Problem: minor flaws in comments

Solution: minor fixes to comments
Problem: poor style in zyre_test

Solution: delete ugly code. If it doesn't look right it doesn't
deserve to survive.
Problem: license.xml is not in obvious place

Solution: move to root directory.
Merge pull request #276 from hintjens/master

Problem: zproject was generating zyre_prelude.h
Problem: No builtin way to build for qt-android
Solution: Add qt-android build system and add to travis-ci
Merge pull request #277 from jemc/master

Problem: No builtin way to build for qt-android
Problem: It's inconsitent to have a source file zyre.c and with a header
file zyre_api.h.
Solution:
   * move zyre.h content to zyre_library.h
   * move zyre_api.h to zyre.h
   * include zyre_library.h in zyre.h