Problem: No builtin way to build for qt-android
Solution: Add qt-android build system and add to travis-ci
Problem: ci_build.sh is not executable
Solution: Change its permissions to make it executable
Problem: qt-android build does not fetch dependencies
Solution: clone libzmq in builds/qt-android/ci_build.sh
Merge pull request #789 from jemc/builds-qt-android

Problem: No builtin way to build for qt-android