Drag fixes and improvements

Bug Fixes

• deeps: Add missing RxJs dependencies (f675e66)
• Hide grid lines on item drag out (49294c2), closes #173
• drag: Fix overlapping in different breakpoints after item resize with floating on false (09b7e94), closes #194
• drag: Fix overlapping in different breakpoints after item resize with floating on false (0258d5d)
• drag: Prevent moving item to negative position (0265244), closes #174
• drag: Solve problem with dropping items in single lane (624a9fe), closes #183

Features

• demo: Add reset widgets button (0338921)
• Add new option gristerOptions.lines.backgroundColor