[ Christian Dywan ] * Adopt xvfb.sh script from ui toolkit to run tests * Sort out build warnings and make them always fatal. * Implement Database.removeDoc method and use it in unit test Functionally this is equivalent to replacing the doc with an empty one. (LP: #1243395) * Use new-style qmlrunner log option to enable stdout. * Query improvements and more advanced example. (LP: #1271977, #1271972, #1266478) * Store whole document contents in the results and unit test that. (LP: #1271973)