Extend orderbook 1-2-5 zoom to all levels

[barnabee]

The Chore

Make all levels of zoom for the order book follow the 1-2-5 zoom convention (e.g. in the screenshot we'd have levels 100, 200, 500, 1000, 2000, 5000, 10,000, etc…)

ie. Add:

• 200
• 500
• 2000
• 5000

This should extend in all directions as required for the magnitude of the numbers in question (at the high end) and the number of decimals (at the low end)