Fixed buy pressing with empty fields Taiga issue #594 (https://tree.taiga.io/project/alexeykiselev-waves-full-node/issue/594)
Fixed buy pressing with empty fields
Taiga issue #594 (https://tree.taiga.io/project/alexeykiselev-waves-full-node/issue/594)

wavesplatform/WavesGUI,beregovoy68/WavesGUI,wavesplatform/WavesGUI,wavesplatform/WavesGUI,beregovoy68/WavesGUI,beregovoy68/WavesGUI,wavesplatform/WavesGUI,beregovoy68/WavesGUI