Merge branch 'sakia020'

appveyor.yml

ci/appveyor/build.cmd

ci/travis/before_install.sh

ci/travis/build.sh

ci/travis/qt-installer-noninteractive.qs

src/sakia/core/community.py

src/sakia/core/money/relative_to_past.py

src/sakia/core/wallet.py

src/sakia/tests/unit/core/test_wallet.py