v2.3.0

Changes since v2.2.0:

• Copy flat cells as tab separated text and paste it back as a grid (9ddc4c0)
• Export CSV flat, skipping sub-grids instead of refusing (8fcf728)
• Shrink the column or row when its widest cell gets smaller while typing (8f1a252)
• Change the font size with Ctrl+Shift+mousewheel (94e14b6)