TravisCI: cache pip locally
TravisCI: cache pip locally

qreal/qreal,qreal/qreal,ZiminGrigory/qreal,ZiminGrigory/qreal,qreal/qreal,ZiminGrigory/qreal,ZiminGrigory/qreal,ZiminGrigory/qreal,ZiminGrigory/qreal,qreal/qreal,qreal/qreal,ZiminGrigory/qreal,qreal/qreal,ZiminGrigory/qreal,ZiminGrigory/qreal,qreal/qreal,qreal/qreal,qreal/qreal