Better Calculator per wanderer709

Web extension that features a calculator straight from the web toolbar.

The Better Calculator:
- includes basic arithmetic ( + - * / ) plus exponents, trigonometry, and logarithms.

- respects the order of operations (parentheses first, then exponents, then multiplication and division, and finally addition and subtraction, all left to right).

- responds to both clickable buttons and keyboard commands.

- saves your calculations so they stay with you should you need to (or accidentally) close and reopen the calculator.

- Many of the key commands are easily found, but some might not be. Click the "Help!" button if you are not sure.