Rounding issues and unsafe operations

[tujlaky]

I think this line in the implementation is not safe it could cause rounding issues:

https://github.com/uzyn/bigdenary/blob/master/mod.ts#L31C7-L31C60

For example the following number will fail: 0.0023537

You can see the problem with this if you try the following calculation:

// 23536.999999999996 instead of 23537
0.0023537 * Math.pow(10, 7)

The response will be a float instead of an integer so it will fail with BigInt.

[tujlaky]

You will see the following JS error:

RangeError - The number 23536.999999999996 cannot be converted to a BigInt because it is not an integer